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Williamsport Rgnl AP Weather Records (USW00014778)

Record envelope, standing records and threshold days for Williamsport Rgnl AP (USW00014778), Pennsylvania, United States, with 126 years of record.

Key Facts for Williamsport Rgnl AP

  • Williamsport Rgnl AP (USW00014778) is a weather station in Pennsylvania, United States at 41.24 latitude and -76.92 longitude, 160 m (524 ft) above sea level.
  • The station reports from 1901 to 2026, 126 years of record.
  • 1,464 records set at Williamsport Rgnl AP still stand.
  • Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
  • Williamsport Rgnl AP set a daily record precipitation of 34.8 mm (1.4 in) on 3 September 2026 (provisional).

Provisional Records

Records set in the last 60 days are provisional until they clear the revision window.

About the Station

  • Location: Pennsylvania, United States, 41.24 latitude, -76.92 longitude.
  • Elevation: 160 m (524 ft).
  • Period of record: 1901 to 2026, 126 years.
  • Eligible elements: tmax, tmin, prcp, snow, snwd.

Daily Record Envelope and 2026

12 days at or beyond a record
Daily record high and record low at Williamsport Rgnl AP, with 2026 drawn through them The band shows the record high and record low for each calendar day at Williamsport Rgnl AP. The lines show the 2026 daily maximum and minimum. 12 days in 2026 matched or passed a record. Temperatures are in degrees Celsius. -40-2002040 JanFebMarAprMayJunJulAugSepOctNovDec
The band shows the record high and record low for each calendar day at Williamsport Rgnl AP. The lines show the 2026 daily maximum and minimum. 12 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Williamsport Rgnl AP, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan20.6 C (69.1 F)-28.9 C (-20.0 F)10.0 C (50.0 F)-19.4 C (-2.9 F)
Feb24.4 C (75.9 F)-25.0 C (-13.0 F)15.6 C (60.1 F)-19.4 C (-2.9 F)
Mar30.6 C (87.1 F)-18.9 C (-2.0 F)26.7 C (80.1 F)-8.3 C (17.1 F)
Apr34.4 C (93.9 F)-9.4 C (15.1 F)32.2 C (90.0 F)-5.6 C (21.9 F)
May35.6 C (96.1 F)-2.2 C (28.0 F)34.4 C (93.9 F)0.0 C (32.0 F)
Jun38.9 C (102.0 F)2.2 C (36.0 F)33.3 C (91.9 F)7.2 C (45.0 F)
Jul39.4 C (102.9 F)6.1 C (43.0 F)37.8 C (100.0 F)10.6 C (51.1 F)
Aug37.8 C (100.0 F)3.3 C (37.9 F)31.7 C (89.1 F)10.6 C (51.1 F)
Sep38.9 C (102.0 F)-1.1 C (30.0 F)33.3 C (91.9 F)5.0 C (41.0 F)
Oct32.8 C (91.0 F)-6.7 C (19.9 F)26.7 C (80.1 F)3.3 C (37.9 F)
Nov28.3 C (82.9 F)-13.3 C (8.1 F)n/an/a
Dec21.1 C (70.0 F)-26.1 C (-15.0 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at Williamsport Rgnl AP by the year they were set 1,464 records at Williamsport Rgnl AP still stand. 1979 holds the most, with 37. 0102030401948: 131949: 251950: 271951: 261952: 191953: 341954: 231955: 181956: 251957: 191958: 161959: 211960: 261961: 181962: 271963: 361964: 231965: 301966: 221967: 231968: 161969: 101970: 241971: 181972: 231973: 111974: 151975: 171976: 291977: 231978: 131979: 371980: 171981: 151982: 231983: 191984: 111985: 161986: 111987: 131988: 331989: 161990: 291991: 331992: 91993: 191994: 121995: 211996: 191997: 51998: 211999: 132000: 162001: 142002: 252003: 72004: 72005: 102006: 112007: 172008: 102009: 132010: 132011: 142012: 142013: 112014: 222015: 292016: 232017: 212018: 182019: 92020: 172021: 122022: 142023: 122024: 152025: 122026: 161948195619641972198019881996200420122020
1,464 records at Williamsport Rgnl AP still stand. 1979 holds the most, with 37.
Standing records at Williamsport Rgnl AP by the year they were set
Year setStanding records
194813
194925
195027
195126
195219
195334
195423
195518
195625
195719
195816
195921
196026
196118
196227
196336
196423
196530
196622
196723
196816
196910
197024
197118
197223
197311
197415
197517
197629
197723
197813
197937
198017
198115
198223
198319
198411
198516
198611
198713
198833
198916
199029
199133
19929
199319
199412
199521
199619
19975
199821
199913
200016
200114
200225
20037
20047
200510
200611
200717
200810
200913
201013
201114
201214
201311
201422
201529
201623
201721
201818
20199
202017
202112
202214
202312
202415
202512
202616

All-Time Record Progression

6 new records
When Williamsport Rgnl AP set new all-time records 6 all-time records were set at Williamsport Rgnl AP between 21 January 1978 and 12 January 1996. Each dot is a new record. Record snow depthRecord low maximum temperatureRecord high maximum temperatureRecord low minimum temperatureRecord high minimum temperature21 January 1978: Record snow depth 61.0 cm (24.0 in)17 January 1982: Record low maximum temperature -17.8 C (0.0 F)16 July 1988: Record high maximum temperature 39.4 C (102.9 F)21 January 1994: Record low minimum temperature -28.9 C (-20.0 F)15 July 1995: Record high minimum temperature 25.6 C (78.1 F)12 January 1996: Record snow depth 66.0 cm (26.0 in)1980198519901995
6 all-time records were set at Williamsport Rgnl AP between 21 January 1978 and 12 January 1996. Each dot is a new record.
When Williamsport Rgnl AP set new all-time records
DateKindDetail
1978-01-21Record snow depthRecord snow depth 61.0 cm (24.0 in)
1982-01-17Record low maximum temperatureRecord low maximum temperature -17.8 C (0.0 F)
1988-07-16Record high maximum temperatureRecord high maximum temperature 39.4 C (102.9 F)
1994-01-21Record low minimum temperatureRecord low minimum temperature -28.9 C (-20.0 F)
1995-07-15Record high minimum temperatureRecord high minimum temperature 25.6 C (78.1 F)
1996-01-12Record snow depthRecord snow depth 66.0 cm (26.0 in)

Wettest Day of Each Month

Jun: 220.0 mm (8.7 in)
Record daily precipitation for each month at Williamsport Rgnl AP The wettest day on record for each calendar month at Williamsport Rgnl AP. The most was 220.0 mm (8.7 in) on 22 June 1972. 0100200300 Jan: 73.7 mm (2.9 in), 25 January 2010 Jan Feb: 69.1 mm (2.7 in), 13 February 1971 Feb Mar: 67.8 mm (2.7 in), 10 March 2011 Mar Apr: 71.4 mm (2.8 in), 30 April 2020 Apr May: 69.3 mm (2.7 in), 3 May 1954 May Jun: 220.0 mm (8.7 in), 22 June 1972 Jun Jul: 83.6 mm (3.3 in), 30 July 2000 Jul Aug: 134.1 mm (5.3 in), 2 August 2026 Aug Sep: 171.7 mm (6.8 in), 7 September 2011 Sep Oct: 111.3 mm (4.4 in), 14 October 1955 Oct Nov: 93.5 mm (3.7 in), 29 November 2005 Nov Dec: 83.6 mm (3.3 in), 13 December 1983 Dec
The wettest day on record for each calendar month at Williamsport Rgnl AP. The most was 220.0 mm (8.7 in) on 22 June 1972.
Record daily precipitation for each month at Williamsport Rgnl AP
MonthRecord daily precipitation (mm)Date
Jan73.7 mm (2.9 in)25 January 2010
Feb69.1 mm (2.7 in)13 February 1971
Mar67.8 mm (2.7 in)10 March 2011
Apr71.4 mm (2.8 in)30 April 2020
May69.3 mm (2.7 in)3 May 1954
Jun220.0 mm (8.7 in)22 June 1972
Jul83.6 mm (3.3 in)30 July 2000
Aug134.1 mm (5.3 in)2 August 2026
Sep171.7 mm (6.8 in)7 September 2011
Oct111.3 mm (4.4 in)14 October 1955
Nov93.5 mm (3.7 in)29 November 2005
Dec83.6 mm (3.3 in)13 December 1983

Period of Record Coverage

1948 to 2026
Days with data per year at Williamsport Rgnl AP 79 years of record at Williamsport Rgnl AP, 1948 to 2026. 2 years have data for under 90 percent of days and are left out of rankings: 1948, 2026. 1948: 245 of 366 days1949: 365 of 365 days1950: 365 of 365 days1951: 365 of 365 days1952: 366 of 366 days1953: 365 of 365 days1954: 365 of 365 days1955: 365 of 365 days1956: 366 of 366 days1957: 365 of 365 days1958: 365 of 365 days1959: 365 of 365 days1960: 366 of 366 days1961: 365 of 365 days1962: 365 of 365 days1963: 365 of 365 days1964: 366 of 366 days1965: 365 of 365 days1966: 365 of 365 days1967: 365 of 365 days1968: 366 of 366 days1969: 365 of 365 days1970: 365 of 365 days1971: 365 of 365 days1972: 366 of 366 days1973: 365 of 365 days1974: 365 of 365 days1975: 365 of 365 days1976: 366 of 366 days1977: 365 of 365 days1978: 365 of 365 days1979: 365 of 365 days1980: 366 of 366 days1981: 365 of 365 days1982: 365 of 365 days1983: 365 of 365 days1984: 366 of 366 days1985: 365 of 365 days1986: 365 of 365 days1987: 365 of 365 days1988: 366 of 366 days1989: 365 of 365 days1990: 365 of 365 days1991: 365 of 365 days1992: 366 of 366 days1993: 365 of 365 days1994: 365 of 365 days1995: 365 of 365 days1996: 366 of 366 days1997: 365 of 365 days1998: 365 of 365 days1999: 365 of 365 days2000: 366 of 366 days2001: 365 of 365 days2002: 365 of 365 days2003: 365 of 365 days2004: 366 of 366 days2005: 365 of 365 days2006: 365 of 365 days2007: 365 of 365 days2008: 366 of 366 days2009: 365 of 365 days2010: 365 of 365 days2011: 365 of 365 days2012: 366 of 366 days2013: 365 of 365 days2014: 365 of 365 days2015: 365 of 365 days2016: 366 of 366 days2017: 365 of 365 days2018: 365 of 365 days2019: 365 of 365 days2020: 366 of 366 days2021: 365 of 365 days2022: 365 of 365 days2023: 365 of 365 days2024: 366 of 366 days2025: 365 of 365 days2026: 285 of 365 days19501960197019801990200020102020
79 years of record at Williamsport Rgnl AP, 1948 to 2026. 2 years have data for under 90 percent of days and are left out of rankings: 1948, 2026.
Days with data per year at Williamsport Rgnl AP
YearDays with dataShare of yearComplete
194824567%No
1949365100%Yes
1950365100%Yes
1951365100%Yes
1952366100%Yes
1953365100%Yes
1954365100%Yes
1955365100%Yes
1956366100%Yes
1957365100%Yes
1958365100%Yes
1959365100%Yes
1960366100%Yes
1961365100%Yes
1962365100%Yes
1963365100%Yes
1964366100%Yes
1965365100%Yes
1966365100%Yes
1967365100%Yes
1968366100%Yes
1969365100%Yes
1970365100%Yes
1971365100%Yes
1972366100%Yes
1973365100%Yes
1974365100%Yes
1975365100%Yes
1976366100%Yes
1977365100%Yes
1978365100%Yes
1979365100%Yes
1980366100%Yes
1981365100%Yes
1982365100%Yes
1983365100%Yes
1984366100%Yes
1985365100%Yes
1986365100%Yes
1987365100%Yes
1988366100%Yes
1989365100%Yes
1990365100%Yes
1991365100%Yes
1992366100%Yes
1993365100%Yes
1994365100%Yes
1995365100%Yes
1996366100%Yes
1997365100%Yes
1998365100%Yes
1999365100%Yes
2000366100%Yes
2001365100%Yes
2002365100%Yes
2003365100%Yes
2004366100%Yes
2005365100%Yes
2006365100%Yes
2007365100%Yes
2008366100%Yes
2009365100%Yes
2010365100%Yes
2011365100%Yes
2012366100%Yes
2013365100%Yes
2014365100%Yes
2015365100%Yes
2016366100%Yes
2017365100%Yes
2018365100%Yes
2019365100%Yes
2020366100%Yes
2021365100%Yes
2022365100%Yes
2023365100%Yes
2024366100%Yes
2025365100%Yes
202628578%No

Latest Records

20
Latest records at Williamsport Rgnl AP
DateStationRecordValueBeat old record byOld record stoodSignificance
3 September 2026Williamsport Rgnl AP, USdaily rain (Provisional)34.8 mm (1.4 in)11.9 mm (0.5 in)32 years23 of 100 (Routine)
6 August 2026Williamsport Rgnl AP, USdaily high min (Tie)22.2 C (72.0 F)tie37 years4 of 100 (Routine)
2 August 2026Williamsport Rgnl AP, USmonthly rain134.1 mm (5.3 in)24.4 mm (1.0 in)37 years47 of 100 (Notable)
3 July 2026Williamsport Rgnl AP, USdaily high min22.8 C (73.0 F)0.6 C (1.1 F)12 years11 of 100 (Routine)
3 July 2026Williamsport Rgnl AP, USdaily high max (Tie)37.8 C (100.0 F)tie60 years6 of 100 (Routine)
2 July 2026Williamsport Rgnl AP, USdaily high max37.8 C (100.0 F)0.6 C (1.1 F)60 years26 of 100 (Routine)
2 July 2026Williamsport Rgnl AP, USdaily high min22.2 C (72.0 F)0.5 C (0.9 F)56 years24 of 100 (Routine)
1 July 2026Williamsport Rgnl AP, USdaily high max37.2 C (99.0 F)2.2 C (4.0 F)72 years34 of 100 (Routine)
23 May 2026Williamsport Rgnl AP, USdaily rain30.5 mm (1.2 in)7.9 mm (0.31 in)47 years29 of 100 (Routine)
23 May 2026Williamsport Rgnl AP, USdaily low max12.2 C (54.0 F)1.7 C (3.1 F)44 years23 of 100 (Routine)
14 May 2026Williamsport Rgnl AP, USdaily low max (Tie)11.1 C (52.0 F)tie65 years6 of 100 (Routine)
12 May 2026Williamsport Rgnl AP, USdaily low min (Tie)0.0 C (32.0 F)tie36 years4 of 100 (Routine)
21 April 2026Williamsport Rgnl AP, USdaily low min-3.9 C (25.0 F)0.6 C (1.1 F)69 years28 of 100 (Routine)
20 April 2026Williamsport Rgnl AP, USdaily low min-2.2 C (28.0 F)0.5 C (0.9 F)52 years23 of 100 (Routine)
16 April 2026Williamsport Rgnl AP, USdaily high min15.0 C (59.0 F)2.2 C (4.0 F)24 years18 of 100 (Routine)
16 April 2026Williamsport Rgnl AP, USdaily high max (Tie)32.2 C (90.0 F)tie24 years3 of 100 (Routine)
15 April 2026Williamsport Rgnl AP, USdaily high max30.6 C (87.1 F)0.6 C (1.1 F)32 years16 of 100 (Routine)
15 April 2026Williamsport Rgnl AP, USdaily high min14.4 C (57.9 F)0.5 C (0.9 F)24 years15 of 100 (Routine)
31 March 2026Williamsport Rgnl AP, USdaily high min11.7 C (53.1 F)1.7 C (3.1 F)28 years18 of 100 (Routine)
26 March 2026Williamsport Rgnl AP, USdaily high max25.0 C (77.0 F)2.2 C (4.0 F)40 years22 of 100 (Routine)

Climate Trend

77 complete years, 1949 to 2025
Annual mean temperature at Williamsport Rgnl AP as warming stripes, 1949 to 2025 One stripe for each of 77 complete years at Williamsport Rgnl AP, 1949 to 2025. Blue stripes are years cooler than the station's own mean of 10.5 C (50.8 F); red stripes are warmer. The coolest year was 1965, at 9.1 C (48.3 F), and the warmest was 2024, at 12.4 C (54.3 F). The strongest colour marks a difference of 2.0 C (3.6 F). 1949: 11.2 C, +0.8 C from the station mean1950: 9.6 C, -0.8 C from the station mean1951: 10.2 C, -0.3 C from the station mean1952: 10.7 C, +0.2 C from the station mean1953: 11.3 C, +0.8 C from the station mean1954: 10.7 C, +0.2 C from the station mean1955: 10.8 C, +0.3 C from the station mean1956: 10.1 C, -0.4 C from the station mean1957: 10.7 C, +0.2 C from the station mean1958: 9.3 C, -1.1 C from the station mean1959: 10.7 C, +0.3 C from the station mean1960: 9.7 C, -0.8 C from the station mean1961: 10.0 C, -0.4 C from the station mean1962: 9.5 C, -1.0 C from the station mean1963: 9.4 C, -1.1 C from the station mean1964: 10.2 C, -0.2 C from the station mean1965: 9.1 C, -1.4 C from the station mean1966: 9.3 C, -1.2 C from the station mean1967: 9.6 C, -0.9 C from the station mean1968: 10.0 C, -0.4 C from the station mean1969: 10.0 C, -0.4 C from the station mean1970: 10.3 C, -0.2 C from the station mean1971: 10.5 C, +0.1 C from the station mean1972: 9.2 C, -1.3 C from the station mean1973: 10.2 C, -0.2 C from the station mean1974: 10.0 C, -0.5 C from the station mean1975: 10.3 C, -0.2 C from the station mean1976: 9.9 C, -0.6 C from the station mean1977: 10.4 C, 0.0 C from the station mean1978: 9.8 C, -0.7 C from the station mean1979: 10.1 C, -0.4 C from the station mean1980: 9.8 C, -0.6 C from the station mean1981: 10.5 C, 0.0 C from the station mean1982: 9.5 C, -1.0 C from the station mean1983: 9.7 C, -0.7 C from the station mean1984: 9.7 C, -0.7 C from the station mean1985: 10.2 C, -0.3 C from the station mean1986: 10.2 C, -0.2 C from the station mean1987: 10.4 C, -0.1 C from the station mean1988: 10.1 C, -0.4 C from the station mean1989: 9.7 C, -0.8 C from the station mean1990: 11.4 C, +1.0 C from the station mean1991: 11.7 C, +1.2 C from the station mean1992: 10.2 C, -0.3 C from the station mean1993: 10.4 C, -0.1 C from the station mean1994: 9.9 C, -0.5 C from the station mean1995: 10.3 C, -0.2 C from the station mean1996: 9.3 C, -1.1 C from the station mean1997: 9.6 C, -0.9 C from the station mean1998: 11.6 C, +1.2 C from the station mean1999: 10.7 C, +0.2 C from the station mean2000: 10.0 C, -0.4 C from the station mean2001: 10.8 C, +0.3 C from the station mean2002: 11.0 C, +0.6 C from the station mean2003: 9.6 C, -0.8 C from the station mean2004: 10.3 C, -0.2 C from the station mean2005: 10.5 C, 0.0 C from the station mean2006: 11.4 C, +0.9 C from the station mean2007: 10.7 C, +0.3 C from the station mean2008: 10.4 C, 0.0 C from the station mean2009: 10.7 C, +0.2 C from the station mean2010: 11.5 C, +1.1 C from the station mean2011: 11.2 C, +0.7 C from the station mean2012: 12.1 C, +1.6 C from the station mean2013: 10.4 C, 0.0 C from the station mean2014: 9.7 C, -0.7 C from the station mean2015: 10.9 C, +0.4 C from the station mean2016: 12.0 C, +1.5 C from the station mean2017: 11.9 C, +1.4 C from the station mean2018: 11.2 C, +0.7 C from the station mean2019: 10.9 C, +0.5 C from the station mean2020: 11.8 C, +1.4 C from the station mean2021: 11.8 C, +1.4 C from the station mean2022: 11.1 C, +0.7 C from the station mean2023: 12.2 C, +1.7 C from the station mean2024: 12.4 C, +1.9 C from the station mean2025: 11.2 C, +0.7 C from the station mean19491960197019801990200020102020
One stripe for each of 77 complete years at Williamsport Rgnl AP, 1949 to 2025. Blue stripes are years cooler than the station's own mean of 10.5 C (50.8 F); red stripes are warmer. The coolest year was 1965, at 9.1 C (48.3 F), and the warmest was 2024, at 12.4 C (54.3 F). The strongest colour marks a difference of 2.0 C (3.6 F).
Annual mean temperature at Williamsport Rgnl AP as warming stripes, 1949 to 2025
YearAnnual mean temperatureDifference from the station mean
194911.2 C+0.76 C
19509.6 C-0.82 C
195110.2 C-0.28 C
195210.7 C+0.24 C
195311.3 C+0.83 C
195410.7 C+0.24 C
195510.8 C+0.29 C
195610.1 C-0.39 C
195710.7 C+0.22 C
19589.3 C-1.15 C
195910.7 C+0.26 C
19609.7 C-0.77 C
196110.0 C-0.45 C
19629.5 C-1.01 C
19639.4 C-1.09 C
196410.2 C-0.22 C
19659.1 C-1.41 C
19669.3 C-1.20 C
19679.6 C-0.90 C
196810.0 C-0.43 C
196910.0 C-0.45 C
197010.3 C-0.17 C
197110.5 C+0.06 C
19729.2 C-1.28 C
197310.2 C-0.22 C
197410.0 C-0.47 C
197510.3 C-0.17 C
19769.9 C-0.58 C
197710.4 C-0.02 C
19789.8 C-0.66 C
197910.1 C-0.38 C
19809.8 C-0.63 C
198110.5 C-0.01 C
19829.5 C-0.96 C
19839.7 C-0.74 C
19849.7 C-0.75 C
198510.2 C-0.27 C
198610.2 C-0.25 C
198710.4 C-0.11 C
198810.1 C-0.39 C
19899.7 C-0.77 C
199011.4 C+0.95 C
199111.7 C+1.22 C
199210.2 C-0.28 C
199310.4 C-0.09 C
19949.9 C-0.54 C
199510.3 C-0.17 C
19969.3 C-1.14 C
19979.6 C-0.91 C
199811.6 C+1.18 C
199910.7 C+0.22 C
200010.0 C-0.45 C
200110.8 C+0.33 C
200211.0 C+0.56 C
20039.6 C-0.82 C
200410.3 C-0.21 C
200510.5 C+0.02 C
200611.4 C+0.91 C
200710.7 C+0.26 C
200810.4 C-0.04 C
200910.7 C+0.20 C
201011.5 C+1.07 C
201111.2 C+0.73 C
201212.1 C+1.62 C
201310.4 C-0.05 C
20149.7 C-0.72 C
201510.9 C+0.40 C
201612.0 C+1.53 C
201711.9 C+1.43 C
201811.2 C+0.70 C
201910.9 C+0.48 C
202011.8 C+1.35 C
202111.8 C+1.36 C
202211.1 C+0.65 C
202312.2 C+1.74 C
202412.4 C+1.92 C
202511.2 C+0.72 C

The annual mean temperature here has risen by 0.2 C (0.1 to 0.3) per decade over 1949 to 2025. In Fahrenheit: 0.3 F (0.2 to 0.5) per decade. The slope is a straight line fitted to 77 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Williamsport Rgnl AP
MeasurePer decade (C)Per decade (F)PeriodComplete yearsReading
Annual mean temperature0.2 C (0.1 to 0.3) per decade0.3 F (0.2 to 0.5) per decade1949 to 202577Rise
Mean daily maximum0.2 C (0.1 to 0.3) per decade0.3 F (0.2 to 0.5) per decade1949 to 202577Rise
Mean daily minimum0.2 C (0.1 to 0.3) per decade0.4 F (0.2 to 0.5) per decade1949 to 202577Rise

A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.

Extremes by Year

1901 to 2026
Yearly extremes at Williamsport Rgnl AP: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)39.4 C (102.9 F)198835.6 C (96.1 F)79
Coldest night (TNn)-28.9 C (-20.0 F)1994-20.0 C (-4.0 F)79
Wettest day (Rx1day)220.0 mm (8.7 in)197261.5 mm (2.4 in)79
Wettest five days (Rx5day)342.2 mm (13.5 in)197293.7 mm (3.7 in)79
Longest dry spell (CDD)35 days202317 days79

Hottest day (TXx)

Hottest day (TXx) at Williamsport Rgnl AP by year The hottest day of the year at Williamsport Rgnl AP, 1901 to 2026. The record is 39.4 C (102.9 F) in 1988, marked on the chart; the median year is 35.6 C (96.1 F). 303234363840192019401960198020002020Record: 39.4 C (102.9 F) in 1988
The hottest day of the year at Williamsport Rgnl AP, 1901 to 2026. The record is 39.4 C (102.9 F) in 1988, marked on the chart; the median year is 35.6 C (96.1 F).
Hottest day (TXx) at Williamsport Rgnl AP by year
YearHottest day (TXx)
1901n/a
194836.7 C (98.1 F)
194937.8 C (100.0 F)
195032.8 C (91.0 F)
195135.6 C (96.1 F)
195238.9 C (102.0 F)
195338.9 C (102.0 F)
195437.2 C (99.0 F)
195537.8 C (100.0 F)
195636.7 C (98.1 F)
195736.1 C (97.0 F)
195834.4 C (93.9 F)
195935.6 C (96.1 F)
196033.9 C (93.0 F)
196133.9 C (93.0 F)
196235.0 C (95.0 F)
196335.0 C (95.0 F)
196436.7 C (98.1 F)
196533.9 C (93.0 F)
196637.8 C (100.0 F)
196733.3 C (91.9 F)
196835.0 C (95.0 F)
196935.0 C (95.0 F)
197032.2 C (90.0 F)
197134.4 C (93.9 F)
197232.8 C (91.0 F)
197336.1 C (97.0 F)
197433.3 C (91.9 F)
197534.4 C (93.9 F)
197633.3 C (91.9 F)
197733.3 C (91.9 F)
197835.0 C (95.0 F)
197931.7 C (89.1 F)
198036.1 C (97.0 F)
198135.0 C (95.0 F)
198232.8 C (91.0 F)
198335.6 C (96.1 F)
198433.9 C (93.0 F)
198534.4 C (93.9 F)
198634.4 C (93.9 F)
198735.6 C (96.1 F)
198839.4 C (102.9 F)
198934.4 C (93.9 F)
199037.8 C (100.0 F)
199138.3 C (100.9 F)
199233.9 C (93.0 F)
199336.7 C (98.1 F)
199436.1 C (97.0 F)
199539.4 C (102.9 F)
199635.6 C (96.1 F)
199736.1 C (97.0 F)
199833.3 C (91.9 F)
199936.1 C (97.0 F)
200033.3 C (91.9 F)
200137.2 C (99.0 F)
200236.1 C (97.0 F)
200333.9 C (93.0 F)
200432.8 C (91.0 F)
200535.6 C (96.1 F)
200635.6 C (96.1 F)
200737.2 C (99.0 F)
200836.1 C (97.0 F)
200934.4 C (93.9 F)
201037.2 C (99.0 F)
201139.4 C (102.9 F)
201237.2 C (99.0 F)
201335.0 C (95.0 F)
201432.8 C (91.0 F)
201533.3 C (91.9 F)
201637.2 C (99.0 F)
201735.0 C (95.0 F)
201836.1 C (97.0 F)
201935.0 C (95.0 F)
202037.8 C (100.0 F)
202135.6 C (96.1 F)
202236.7 C (98.1 F)
202335.6 C (96.1 F)
202436.7 C (98.1 F)
202536.7 C (98.1 F)
202637.8 C (100.0 F)

Coldest night (TNn)

Coldest night (TNn) at Williamsport Rgnl AP by year The coldest night of the year at Williamsport Rgnl AP, 1901 to 2026. The record is -28.9 C (-20.0 F) in 1994, marked on the chart; the median year is -20.0 C (-4.0 F). -30-25-20-15-10192019401960198020002020Record: -28.9 C (-20.0 F) in 1994
The coldest night of the year at Williamsport Rgnl AP, 1901 to 2026. The record is -28.9 C (-20.0 F) in 1994, marked on the chart; the median year is -20.0 C (-4.0 F).
Coldest night (TNn) at Williamsport Rgnl AP by year
YearColdest night (TNn)
1901n/a
1948-17.8 C (0.0 F)
1949-18.9 C (-2.0 F)
1950-26.1 C (-15.0 F)
1951-23.9 C (-11.0 F)
1952-16.1 C (3.0 F)
1953-14.4 C (6.1 F)
1954-20.6 C (-5.1 F)
1955-20.6 C (-5.1 F)
1956-13.3 C (8.1 F)
1957-23.3 C (-9.9 F)
1958-20.6 C (-5.1 F)
1959-19.4 C (-2.9 F)
1960-23.9 C (-11.0 F)
1961-25.0 C (-13.0 F)
1962-19.4 C (-2.9 F)
1963-24.4 C (-11.9 F)
1964-23.9 C (-11.0 F)
1965-21.7 C (-7.1 F)
1966-19.4 C (-2.9 F)
1967-22.8 C (-9.0 F)
1968-23.9 C (-11.0 F)
1969-23.3 C (-9.9 F)
1970-25.0 C (-13.0 F)
1971-25.0 C (-13.0 F)
1972-21.1 C (-6.0 F)
1973-23.3 C (-9.9 F)
1974-15.6 C (3.9 F)
1975-19.4 C (-2.9 F)
1976-20.0 C (-4.0 F)
1977-27.2 C (-17.0 F)
1978-19.4 C (-2.9 F)
1979-24.4 C (-11.9 F)
1980-25.0 C (-13.0 F)
1981-24.4 C (-11.9 F)
1982-24.4 C (-11.9 F)
1983-19.4 C (-2.9 F)
1984-25.0 C (-13.0 F)
1985-25.6 C (-14.1 F)
1986-17.2 C (1.0 F)
1987-20.6 C (-5.1 F)
1988-22.2 C (-8.0 F)
1989-22.8 C (-9.0 F)
1990-15.6 C (3.9 F)
1991-15.6 C (3.9 F)
1992-15.0 C (5.0 F)
1993-19.4 C (-2.9 F)
1994-28.9 C (-20.0 F)
1995-19.4 C (-2.9 F)
1996-21.1 C (-6.0 F)
1997-22.2 C (-8.0 F)
1998-19.4 C (-2.9 F)
1999-16.7 C (1.9 F)
2000-20.0 C (-4.0 F)
2001-14.4 C (6.1 F)
2002-16.1 C (3.0 F)
2003-17.8 C (0.0 F)
2004-18.3 C (-0.9 F)
2005-21.1 C (-6.0 F)
2006-12.8 C (9.0 F)
2007-16.7 C (1.9 F)
2008-15.0 C (5.0 F)
2009-25.0 C (-13.0 F)
2010-13.9 C (7.0 F)
2011-21.1 C (-6.0 F)
2012-13.9 C (7.0 F)
2013-17.2 C (1.0 F)
2014-21.6 C (-6.9 F)
2015-22.7 C (-8.9 F)
2016-18.2 C (-0.8 F)
2017-15.5 C (4.1 F)
2018-19.9 C (-3.8 F)
2019-21.0 C (-5.8 F)
2020-15.5 C (4.1 F)
2021-14.3 C (6.3 F)
2022-19.3 C (-2.7 F)
2023-15.5 C (4.1 F)
2024-15.5 C (4.1 F)
2025-20.5 C (-4.9 F)
2026-19.4 C (-2.9 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at Williamsport Rgnl AP by year The wettest day of the year at Williamsport Rgnl AP, 1901 to 2026. The record is 220.0 mm (8.7 in) in 1972, marked on the chart; the median year is 61.5 mm (2.4 in). 050100150200250192019401960198020002020Record: 220.0 mm (8.7 in) in 1972
The wettest day of the year at Williamsport Rgnl AP, 1901 to 2026. The record is 220.0 mm (8.7 in) in 1972, marked on the chart; the median year is 61.5 mm (2.4 in).
Wettest day (Rx1day) at Williamsport Rgnl AP by year
YearWettest day (Rx1day)
1901n/a
194848.0 mm (1.9 in)
194954.6 mm (2.1 in)
195062.0 mm (2.4 in)
195140.9 mm (1.6 in)
195257.2 mm (2.3 in)
195356.9 mm (2.2 in)
195469.3 mm (2.7 in)
1955111.3 mm (4.4 in)
195676.2 mm (3.0 in)
195761.0 mm (2.4 in)
195864.0 mm (2.5 in)
195948.0 mm (1.9 in)
196044.7 mm (1.8 in)
196157.4 mm (2.3 in)
196294.0 mm (3.7 in)
196356.4 mm (2.2 in)
196460.5 mm (2.4 in)
196537.3 mm (1.5 in)
196686.4 mm (3.4 in)
196752.8 mm (2.1 in)
196861.5 mm (2.4 in)
196938.6 mm (1.5 in)
197049.8 mm (2.0 in)
197169.1 mm (2.7 in)
1972220.0 mm (8.7 in)
197371.9 mm (2.8 in)
197450.8 mm (2.0 in)
1975100.6 mm (4.0 in)
197667.1 mm (2.6 in)
197753.1 mm (2.1 in)
197849.3 mm (1.9 in)
197950.3 mm (2.0 in)
198063.2 mm (2.5 in)
198156.1 mm (2.2 in)
198269.9 mm (2.8 in)
198383.6 mm (3.3 in)
198461.5 mm (2.4 in)
198539.1 mm (1.5 in)
198649.3 mm (1.9 in)
198741.1 mm (1.6 in)
1988109.7 mm (4.3 in)
198952.6 mm (2.1 in)
199074.9 mm (2.9 in)
199152.1 mm (2.1 in)
199238.4 mm (1.5 in)
199345.2 mm (1.8 in)
199460.2 mm (2.4 in)
199573.4 mm (2.9 in)
199672.1 mm (2.8 in)
199729.2 mm (1.1 in)
199845.2 mm (1.8 in)
1999159.8 mm (6.3 in)
200083.6 mm (3.3 in)
200154.9 mm (2.2 in)
200257.2 mm (2.3 in)
200365.5 mm (2.6 in)
2004141.7 mm (5.6 in)
200593.5 mm (3.7 in)
200698.3 mm (3.9 in)
200747.2 mm (1.9 in)
200876.2 mm (3.0 in)
200945.0 mm (1.8 in)
201099.3 mm (3.9 in)
2011171.7 mm (6.8 in)
201254.4 mm (2.1 in)
201335.8 mm (1.4 in)
201486.4 mm (3.4 in)
201553.3 mm (2.1 in)
201665.8 mm (2.6 in)
201784.6 mm (3.3 in)
201880.0 mm (3.1 in)
201947.2 mm (1.9 in)
202071.4 mm (2.8 in)
202171.9 mm (2.8 in)
202243.4 mm (1.7 in)
202383.6 mm (3.3 in)
202483.8 mm (3.3 in)
202563.2 mm (2.5 in)
2026134.1 mm (5.3 in)

Wettest five days (Rx5day)

Wettest five days (Rx5day) at Williamsport Rgnl AP by year The wettest five days of the year at Williamsport Rgnl AP, 1901 to 2026. The record is 342.2 mm (13.5 in) in 1972, marked on the chart; the median year is 93.7 mm (3.7 in). 0100200300400192019401960198020002020Record: 342.2 mm (13.5 in) in 1972
The wettest five days of the year at Williamsport Rgnl AP, 1901 to 2026. The record is 342.2 mm (13.5 in) in 1972, marked on the chart; the median year is 93.7 mm (3.7 in).
Wettest five days (Rx5day) at Williamsport Rgnl AP by year
YearWettest five days (Rx5day)
1901n/a
194866.6 mm (2.6 in)
194980.2 mm (3.2 in)
1950129.1 mm (5.1 in)
195161.7 mm (2.4 in)
1952133.1 mm (5.2 in)
195366.9 mm (2.6 in)
195495.5 mm (3.8 in)
1955130.7 mm (5.1 in)
195696.0 mm (3.8 in)
195793.7 mm (3.7 in)
195888.7 mm (3.5 in)
195995.3 mm (3.8 in)
196095.7 mm (3.8 in)
196180.2 mm (3.2 in)
1962103.3 mm (4.1 in)
196367.6 mm (2.7 in)
196475.8 mm (3.0 in)
196566.3 mm (2.6 in)
196690.6 mm (3.6 in)
196770.1 mm (2.8 in)
1968107.0 mm (4.2 in)
196975.8 mm (3.0 in)
197076.7 mm (3.0 in)
197182.5 mm (3.2 in)
1972342.2 mm (13.5 in)
197388.7 mm (3.5 in)
197486.7 mm (3.4 in)
1975206.2 mm (8.1 in)
1976116.3 mm (4.6 in)
1977116.4 mm (4.6 in)
1978100.6 mm (4.0 in)
197979.5 mm (3.1 in)
198064.0 mm (2.5 in)
198199.6 mm (3.9 in)
1982121.4 mm (4.8 in)
1983105.7 mm (4.2 in)
198499.1 mm (3.9 in)
198564.5 mm (2.5 in)
198679.0 mm (3.1 in)
198762.2 mm (2.4 in)
1988140.4 mm (5.5 in)
198988.2 mm (3.5 in)
1990128.7 mm (5.1 in)
199166.1 mm (2.6 in)
199278.2 mm (3.1 in)
199372.6 mm (2.9 in)
199496.1 mm (3.8 in)
199598.5 mm (3.9 in)
1996126.3 mm (5.0 in)
199763.0 mm (2.5 in)
199885.4 mm (3.4 in)
1999185.9 mm (7.3 in)
2000140.6 mm (5.5 in)
200179.5 mm (3.1 in)
2002102.9 mm (4.1 in)
200394.5 mm (3.7 in)
2004168.9 mm (6.6 in)
200599.4 mm (3.9 in)
2006184.1 mm (7.2 in)
200789.1 mm (3.5 in)
200892.7 mm (3.6 in)
200976.7 mm (3.0 in)
2010163.0 mm (6.4 in)
2011257.7 mm (10.1 in)
201265.1 mm (2.6 in)
201362.5 mm (2.5 in)
2014110.1 mm (4.3 in)
201572.4 mm (2.9 in)
201680.5 mm (3.2 in)
2017102.1 mm (4.0 in)
2018191.0 mm (7.5 in)
201977.2 mm (3.0 in)
202088.7 mm (3.5 in)
202197.8 mm (3.9 in)
202280.7 mm (3.2 in)
2023109.0 mm (4.3 in)
2024117.8 mm (4.6 in)
202567.2 mm (2.6 in)
2026137.4 mm (5.4 in)

Longest dry spell (CDD)

Longest dry spell (CDD) at Williamsport Rgnl AP by year The longest dry spell of the year at Williamsport Rgnl AP, 1901 to 2026. The record is 35 days in 2023, marked on the chart; the median year is 17 days. 010203040192019401960198020002020Record: 35 days in 2023
The longest dry spell of the year at Williamsport Rgnl AP, 1901 to 2026. The record is 35 days in 2023, marked on the chart; the median year is 17 days.
Longest dry spell (CDD) at Williamsport Rgnl AP by year
YearLongest dry spell (CDD)
1901n/a
194814 days
194921 days
195016 days
195119 days
195217 days
195318 days
195416 days
195517 days
195614 days
195713 days
195822 days
195913 days
196016 days
196118 days
196217 days
196327 days
196427 days
196515 days
196617 days
196719 days
196817 days
196918 days
19709 days
197116 days
197211 days
197317 days
197415 days
197517 days
197619 days
197714 days
197817 days
197915 days
198027 days
198119 days
198213 days
198315 days
198416 days
198519 days
198623 days
198723 days
198825 days
198916 days
199013 days
199123 days
199218 days
199318 days
199419 days
199516 days
199615 days
199721 days
199819 days
199917 days
200015 days
200130 days
200213 days
200322 days
200417 days
200518 days
200620 days
200714 days
200824 days
200920 days
201019 days
201111 days
201215 days
201312 days
201421 days
201516 days
201617 days
201716 days
201814 days
201910 days
202015 days
202116 days
202215 days
202335 days
202427 days
202516 days
202620 days

Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.

Frost Dates and Growing Season

77 years with a frost

Across 77 years with a frost, the median last spring frost at Williamsport Rgnl AP falls on 28 April and the median first autumn frost on 18 October, which leaves a median of 171 days between them.

In 1996 to 2025 the median growing season was 176 days. That is 7 days more than in 1949 to 1978.

Fitted over all years, the growing season changes by +1.7 days per decade at this station.

Frost dates and growing season at Williamsport Rgnl AP
MeasureMedian, all yearsEarliest period (1949 to 1978)Recent period (1996 to 2025)Recent against earliestFitted trend
Last spring frost28 April29 April28 April1 day earlier-0.1 days per decade
First autumn frost18 October15 October23 October8 days later+1.5 days per decade
Growing days171 days169 days176 days7 days more+1.7 days per decade

A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.

Rainfall Return Levels

77 years, 1949 to 2025

A day with at least 60.8 mm (2.4 in) of rain is expected about once in 2 years. A day with at least 191.3 mm (7.5 in) of rain is expected about once in 100 years.

Rainfall return levels at Williamsport Rgnl AP: the daily rain expected about once in a given number of years
Expected about once inA day with at leastNote
2 years60.8 mm (2.4 in)
5 years83.9 mm (3.3 in)
10 years103.1 mm (4.1 in)
25 years132.8 mm (5.2 in)
50 years159.7 mm (6.3 in)
100 years191.3 mm (7.5 in)Longer than the 77 years of record

The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 77 years of values from 1949 to 2025.

A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.

The largest wettest-day totals in the fit: 220.0 mm (8.7 in) in 1972; 171.7 mm (6.8 in) in 2011; 159.8 mm (6.3 in) in 1999.

Station Changes

No change in the annual mean temperature of this station was found against its neighbours.

Climate Twins

2011 to 2025 against 1961 to 1990

Over 2011 to 2025, Williamsport Rgnl AP had a mean temperature of 11.4 C (52.5 F) and 1,127.0 mm (44.4 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Conowingo Dam (United States, 187 km away), Emmitsburg 2 SE (United States, 177 km away) and Willow Grove NAS (United States, 189 km away).

Climate twins of Williamsport Rgnl AP: stations whose 1961 to 1990 climate is closest to its 2011 to 2025 climate
Twin stationCountryDistance awayMean temperature, 1961-1990Rain a year, 1961-1990Climate difference
Conowingo DamUnited States187 km (116 mi)11.7 C (53.0 F)1,118.5 mm (44.0 in)0.54
Emmitsburg 2 SEUnited States177 km (110 mi)11.4 C (52.6 F)1,092.5 mm (43.0 in)0.60
Willow Grove NASUnited States189 km (117 mi)11.6 C (52.9 F)1,157.6 mm (45.6 in)0.61

Twins are stations, not cities. A twin is one of the three stations at least 100 km away whose earlier climate is closest to this station's recent one, so a close match does not mean the two places look alike in other ways. A station move or a gap in a record can change that station's averages. The list describes past climate; it is not a forecast and does not say what caused any change. How twins are found, and a search for any station.

Download the Data

  • Data for Williamsport Rgnl AP standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for Williamsport Rgnl AP threshold days by year: CSV or JSON. Field meanings are on the data page.

Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-15 (15 October 2026). Records are computed by this site and are not official.

Data as of . Last revised (2026-10-15).