Record envelope, standing records and threshold days for Williamsport (USC00369733), Pennsylvania, United States, with 55 years of record.
Key Facts for Williamsport
Williamsport (USC00369733) is a weather station in Pennsylvania, United States at 41.23 latitude and -77.00 longitude, 151 m (495 ft) above sea level.
The station reports from 1895 to 1949, 55 years of record.
1,464 records set at Williamsport still stand.
Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
Williamsport set a daily record precipitation of 49.3 mm (1.9 in) on 14 September 1949.
About the Station
Location: Pennsylvania, United States, 41.23 latitude, -77.00 longitude.
Elevation: 151 m (495 ft).
Period of record: 1895 to 1949, 55 years.
Eligible elements: tmax, tmin, prcp.
Daily Record Envelope and 2026
0 days at or beyond a record
Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Williamsport. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Williamsport, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
21.1 C (70.0 F)
-27.2 C (-17.0 F)
n/a
n/a
Feb
20.6 C (69.1 F)
-27.8 C (-18.0 F)
n/a
n/a
Mar
30.0 C (86.0 F)
-20.6 C (-5.1 F)
n/a
n/a
Apr
35.6 C (96.1 F)
-13.3 C (8.1 F)
n/a
n/a
May
35.6 C (96.1 F)
-2.2 C (28.0 F)
n/a
n/a
Jun
40.0 C (104.0 F)
2.2 C (36.0 F)
n/a
n/a
Jul
41.1 C (106.0 F)
6.1 C (43.0 F)
n/a
n/a
Aug
39.4 C (102.9 F)
3.3 C (37.9 F)
n/a
n/a
Sep
37.8 C (100.0 F)
-0.6 C (30.9 F)
n/a
n/a
Oct
33.9 C (93.0 F)
-7.2 C (19.0 F)
n/a
n/a
Nov
26.1 C (79.0 F)
-16.1 C (3.0 F)
n/a
n/a
Dec
20.0 C (68.0 F)
-24.4 C (-11.9 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Williamsport still stand. 1896 holds the most, with 44.
Standing records at Williamsport by the year they were set
Year set
Standing records
1895
42
1896
44
1897
23
1898
31
1899
38
1900
29
1901
41
1902
21
1903
40
1904
26
1905
19
1906
33
1907
20
1908
21
1909
34
1910
17
1911
31
1912
37
1913
26
1914
39
1915
19
1916
22
1917
31
1918
40
1919
16
1920
25
1921
24
1922
28
1923
26
1924
16
1925
38
1926
23
1927
33
1928
21
1929
41
1930
44
1931
37
1932
31
1933
29
1934
36
1935
25
1936
35
1937
15
1938
31
1939
17
1940
39
1941
27
1942
27
1943
29
1944
14
1945
13
All-Time Record Progression
4 new records
4 all-time records were set at Williamsport between 5 June 1925 and 9 July 1936. Each dot is a new record.
When Williamsport set new all-time records
Date
Kind
Detail
1925-06-05
Record high maximum temperature
Record high maximum temperature 40.0 C (104.0 F)
1933-08-24
Record daily precipitation
Record daily precipitation 132.6 mm (5.2 in)
1934-02-28
Record low minimum temperature
Record low minimum temperature -27.8 C (-18.0 F)
1936-07-09
Record high maximum temperature
Record high maximum temperature 41.1 C (106.0 F)
Wettest Day of Each Month
Aug: 132.6 mm (5.2 in)
The wettest day on record for each calendar month at Williamsport. The most was 132.6 mm (5.2 in) on 24 August 1933.
Record daily precipitation for each month at Williamsport
Month
Record daily precipitation (mm)
Date
Jan
67.3 mm (2.6 in)
7 January 1905
Feb
66.3 mm (2.6 in)
22 February 1937
Mar
59.9 mm (2.4 in)
8 March 1930
Apr
83.1 mm (3.3 in)
30 April 1909
May
89.7 mm (3.5 in)
21 May 1919
Jun
82.8 mm (3.3 in)
24 June 1907
Jul
78.5 mm (3.1 in)
6 July 1928
Aug
132.6 mm (5.2 in)
24 August 1933
Sep
99.1 mm (3.9 in)
30 September 1924
Oct
87.6 mm (3.4 in)
3 October 1929
Nov
68.6 mm (2.7 in)
16 November 1926
Dec
78.5 mm (3.1 in)
14 December 1901
Period of Record Coverage
1895 to 1945
Complete yearUnder 90 percent of days
51 years of record at Williamsport, 1895 to 1945. 2 years have data for under 90 percent of days and are left out of rankings: 1895, 1945.
Cooler than the station meanWarmer than the station mean
One stripe for each of 47 complete years at Williamsport, 1896 to 1943. Blue stripes are years cooler than the station's own mean of 10.4 C (50.7 F); red stripes are warmer. The coolest year was 1904, at 8.8 C (47.9 F), and the warmest was 1921, at 12.0 C (53.6 F). The strongest colour marks a difference of 1.7 C (3.1 F).
Annual mean temperature at Williamsport as warming stripes, 1896 to 1943
Year
Annual mean temperature
Difference from the station mean
1896
9.9 C
-0.48 C
1897
10.0 C
-0.39 C
1898
10.8 C
+0.46 C
1899
10.3 C
-0.10 C
1900
11.0 C
+0.58 C
1901
9.9 C
-0.48 C
1902
9.9 C
-0.52 C
1903
10.2 C
-0.13 C
1904
8.8 C
-1.55 C
1905
10.1 C
-0.32 C
1906
10.7 C
+0.32 C
1907
9.4 C
-0.99 C
1908
10.7 C
+0.29 C
1909
10.3 C
-0.10 C
1910
10.4 C
+0.03 C
1911
11.3 C
+0.95 C
1912
10.1 C
-0.23 C
1913
11.4 C
+1.05 C
1914
10.0 C
-0.38 C
1915
10.4 C
+0.02 C
1916
10.1 C
-0.27 C
1917
8.9 C
-1.48 C
1918
10.5 C
+0.13 C
1919
11.0 C
+0.64 C
1920
10.1 C
-0.29 C
1921
12.0 C
+1.62 C
1922
11.1 C
+0.73 C
1923
10.6 C
+0.27 C
1924
9.7 C
-0.64 C
1925
10.7 C
+0.31 C
1926
9.5 C
-0.87 C
1927
10.2 C
-0.17 C
1928
10.5 C
+0.16 C
1929
10.5 C
+0.13 C
1930
10.7 C
+0.34 C
1931
11.7 C
+1.28 C
1933
11.1 C
+0.69 C
1934
10.5 C
+0.16 C
1935
9.8 C
-0.56 C
1936
10.2 C
-0.16 C
1937
10.4 C
-0.02 C
1938
10.9 C
+0.56 C
1939
10.5 C
+0.14 C
1940
8.9 C
-1.44 C
1941
10.5 C
+0.15 C
1942
11.0 C
+0.65 C
1943
10.4 C
+0.04 C
The fitted trend in annual mean temperature here over 1896 to 1943 is 0.1 C (-0.1 to 0.2) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.1 F (-0.1 to 0.4) per decade. The slope is a straight line fitted to 47 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Williamsport
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.1 C (-0.1 to 0.2) per decade
0.1 F (-0.1 to 0.4) per decade
1896 to 1943
47
Not clearly different from zero
Mean daily maximum
0.3 C (0.1 to 0.5) per decade
0.5 F (0.2 to 0.9) per decade
1896 to 1943
47
Rise
Mean daily minimum
-0.15 C (-0.27 to -0.02) per decade
-0.26 F (-0.49 to -0.04) per decade
1896 to 1943
47
Fall
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
1895 to 1949
Yearly extremes at Williamsport: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
41.1 C (106.0 F)
1936
36.1 C (97.0 F)
51
Coldest night (TNn)
-27.8 C (-18.0 F)
1934
-20.0 C (-4.0 F)
50
Wettest day (Rx1day)
132.6 mm (5.2 in)
1933
62.0 mm (2.4 in)
53
Wettest five days (Rx5day)
171.0 mm (6.7 in)
1912
87.4 mm (3.4 in)
53
Longest dry spell (CDD)
36 days
1908
17 days
53
Hottest day (TXx)
The hottest day of the year at Williamsport, 1895 to 1949. The record is 41.1 C (106.0 F) in 1936, marked on the chart; the median year is 36.1 C (97.0 F).
Hottest day (TXx) at Williamsport by year
Year
Hottest day (TXx)
1895
35.6 C (96.1 F)
1896
33.9 C (93.0 F)
1897
33.9 C (93.0 F)
1898
36.1 C (97.0 F)
1899
34.4 C (93.9 F)
1900
36.7 C (98.1 F)
1901
36.1 C (97.0 F)
1902
33.9 C (93.0 F)
1903
34.4 C (93.9 F)
1904
33.9 C (93.0 F)
1905
33.9 C (93.0 F)
1906
33.9 C (93.0 F)
1907
31.7 C (89.1 F)
1908
34.4 C (93.9 F)
1909
34.4 C (93.9 F)
1910
36.7 C (98.1 F)
1911
37.8 C (100.0 F)
1912
35.0 C (95.0 F)
1913
36.1 C (97.0 F)
1914
34.4 C (93.9 F)
1915
32.2 C (90.0 F)
1916
36.7 C (98.1 F)
1917
36.7 C (98.1 F)
1918
39.4 C (102.9 F)
1919
37.2 C (99.0 F)
1920
35.6 C (96.1 F)
1921
36.1 C (97.0 F)
1922
35.6 C (96.1 F)
1923
38.3 C (100.9 F)
1924
36.7 C (98.1 F)
1925
40.0 C (104.0 F)
1926
37.8 C (100.0 F)
1927
36.7 C (98.1 F)
1928
35.0 C (95.0 F)
1929
36.7 C (98.1 F)
1930
38.9 C (102.0 F)
1931
38.9 C (102.0 F)
1932
38.3 C (100.9 F)
1933
37.8 C (100.0 F)
1934
38.3 C (100.9 F)
1935
35.6 C (96.1 F)
1936
41.1 C (106.0 F)
1937
35.0 C (95.0 F)
1938
36.1 C (97.0 F)
1939
35.6 C (96.1 F)
1940
34.4 C (93.9 F)
1941
36.7 C (98.1 F)
1942
35.6 C (96.1 F)
1943
36.1 C (97.0 F)
1944
38.3 C (100.9 F)
1945
35.6 C (96.1 F)
1948
n/a
1949
n/a
Coldest night (TNn)
The coldest night of the year at Williamsport, 1895 to 1949. The record is -27.8 C (-18.0 F) in 1934, marked on the chart; the median year is -20.0 C (-4.0 F).
Coldest night (TNn) at Williamsport by year
Year
Coldest night (TNn)
1895
-20.0 C (-4.0 F)
1896
-20.0 C (-4.0 F)
1897
-17.8 C (0.0 F)
1898
-18.9 C (-2.0 F)
1899
-27.2 C (-17.0 F)
1900
-20.0 C (-4.0 F)
1901
-17.8 C (0.0 F)
1902
-16.1 C (3.0 F)
1903
-20.0 C (-4.0 F)
1904
-27.2 C (-17.0 F)
1905
-20.6 C (-5.1 F)
1906
-18.3 C (-0.9 F)
1907
-22.8 C (-9.0 F)
1908
-22.2 C (-8.0 F)
1909
-21.1 C (-6.0 F)
1910
-20.0 C (-4.0 F)
1911
-13.3 C (8.1 F)
1912
-27.2 C (-17.0 F)
1913
-15.0 C (5.0 F)
1914
-23.3 C (-9.9 F)
1915
-18.3 C (-0.9 F)
1916
-20.6 C (-5.1 F)
1917
-24.4 C (-11.9 F)
1918
-24.4 C (-11.9 F)
1919
-20.0 C (-4.0 F)
1920
-20.6 C (-5.1 F)
1921
-19.4 C (-2.9 F)
1922
-22.2 C (-8.0 F)
1923
-18.3 C (-0.9 F)
1924
-20.6 C (-5.1 F)
1925
-26.7 C (-16.1 F)
1926
-20.6 C (-5.1 F)
1927
-21.1 C (-6.0 F)
1928
-18.9 C (-2.0 F)
1929
-16.7 C (1.9 F)
1930
-19.4 C (-2.9 F)
1931
-16.1 C (3.0 F)
1932
-15.6 C (3.9 F)
1933
-20.0 C (-4.0 F)
1934
-27.8 C (-18.0 F)
1935
-21.1 C (-6.0 F)
1936
-23.3 C (-9.9 F)
1937
-14.4 C (6.1 F)
1938
-18.9 C (-2.0 F)
1939
-18.3 C (-0.9 F)
1940
-17.8 C (0.0 F)
1941
-17.2 C (1.0 F)
1942
-23.3 C (-9.9 F)
1943
-23.3 C (-9.9 F)
1944
-16.1 C (3.0 F)
1945
n/a
1948
n/a
1949
n/a
Wettest day (Rx1day)
The wettest day of the year at Williamsport, 1895 to 1949. The record is 132.6 mm (5.2 in) in 1933, marked on the chart; the median year is 62.0 mm (2.4 in).
Wettest day (Rx1day) at Williamsport by year
Year
Wettest day (Rx1day)
1895
33.0 mm (1.3 in)
1896
80.5 mm (3.2 in)
1897
108.2 mm (4.3 in)
1898
39.1 mm (1.5 in)
1899
50.5 mm (2.0 in)
1900
64.5 mm (2.5 in)
1901
78.5 mm (3.1 in)
1902
63.2 mm (2.5 in)
1903
53.6 mm (2.1 in)
1904
37.1 mm (1.5 in)
1905
67.3 mm (2.6 in)
1906
73.7 mm (2.9 in)
1907
82.8 mm (3.3 in)
1908
60.5 mm (2.4 in)
1909
83.1 mm (3.3 in)
1910
51.1 mm (2.0 in)
1911
56.9 mm (2.2 in)
1912
94.0 mm (3.7 in)
1913
91.9 mm (3.6 in)
1914
43.9 mm (1.7 in)
1915
56.1 mm (2.2 in)
1916
40.9 mm (1.6 in)
1917
73.7 mm (2.9 in)
1918
42.7 mm (1.7 in)
1919
89.7 mm (3.5 in)
1920
48.8 mm (1.9 in)
1921
45.0 mm (1.8 in)
1922
55.9 mm (2.2 in)
1923
64.3 mm (2.5 in)
1924
99.1 mm (3.9 in)
1925
48.8 mm (1.9 in)
1926
68.6 mm (2.7 in)
1927
71.6 mm (2.8 in)
1928
78.5 mm (3.1 in)
1929
87.6 mm (3.4 in)
1930
59.9 mm (2.4 in)
1931
39.6 mm (1.6 in)
1932
65.0 mm (2.6 in)
1933
132.6 mm (5.2 in)
1934
84.3 mm (3.3 in)
1935
63.5 mm (2.5 in)
1936
47.5 mm (1.9 in)
1937
66.5 mm (2.6 in)
1938
100.3 mm (3.9 in)
1939
36.6 mm (1.4 in)
1940
49.0 mm (1.9 in)
1941
91.7 mm (3.6 in)
1942
49.8 mm (2.0 in)
1943
54.9 mm (2.2 in)
1944
58.9 mm (2.3 in)
1945
60.2 mm (2.4 in)
1948
58.4 mm (2.3 in)
1949
62.0 mm (2.4 in)
Wettest five days (Rx5day)
The wettest five days of the year at Williamsport, 1895 to 1949. The record is 171.0 mm (6.7 in) in 1912, marked on the chart; the median year is 87.4 mm (3.4 in).
Wettest five days (Rx5day) at Williamsport by year
Year
Wettest five days (Rx5day)
1895
81.5 mm (3.2 in)
1896
117.1 mm (4.6 in)
1897
108.2 mm (4.3 in)
1898
66.3 mm (2.6 in)
1899
66.4 mm (2.6 in)
1900
67.0 mm (2.6 in)
1901
79.0 mm (3.1 in)
1902
74.2 mm (2.9 in)
1903
74.2 mm (2.9 in)
1904
75.7 mm (3.0 in)
1905
94.2 mm (3.7 in)
1906
85.9 mm (3.4 in)
1907
96.5 mm (3.8 in)
1908
91.2 mm (3.6 in)
1909
109.7 mm (4.3 in)
1910
101.1 mm (4.0 in)
1911
95.0 mm (3.7 in)
1912
171.0 mm (6.7 in)
1913
100.5 mm (4.0 in)
1914
77.2 mm (3.0 in)
1915
79.0 mm (3.1 in)
1916
83.1 mm (3.3 in)
1917
87.4 mm (3.4 in)
1918
82.0 mm (3.2 in)
1919
143.3 mm (5.6 in)
1920
81.6 mm (3.2 in)
1921
70.1 mm (2.8 in)
1922
111.8 mm (4.4 in)
1923
90.8 mm (3.6 in)
1924
117.4 mm (4.6 in)
1925
95.2 mm (3.7 in)
1926
136.4 mm (5.4 in)
1927
82.6 mm (3.3 in)
1928
100.7 mm (4.0 in)
1929
123.2 mm (4.9 in)
1930
66.8 mm (2.6 in)
1931
80.0 mm (3.1 in)
1932
88.1 mm (3.5 in)
1933
146.3 mm (5.8 in)
1934
105.7 mm (4.2 in)
1935
72.4 mm (2.9 in)
1936
119.1 mm (4.7 in)
1937
103.8 mm (4.1 in)
1938
101.3 mm (4.0 in)
1939
70.0 mm (2.8 in)
1940
76.3 mm (3.0 in)
1941
101.6 mm (4.0 in)
1942
80.5 mm (3.2 in)
1943
94.0 mm (3.7 in)
1944
81.8 mm (3.2 in)
1945
69.8 mm (2.7 in)
1948
71.1 mm (2.8 in)
1949
75.9 mm (3.0 in)
Longest dry spell (CDD)
The longest dry spell of the year at Williamsport, 1895 to 1949. The record is 36 days in 1908, marked on the chart; the median year is 17 days.
Longest dry spell (CDD) at Williamsport by year
Year
Longest dry spell (CDD)
1895
21 days
1896
12 days
1897
16 days
1898
14 days
1899
9 days
1900
16 days
1901
23 days
1902
15 days
1903
17 days
1904
16 days
1905
19 days
1906
15 days
1907
13 days
1908
36 days
1909
26 days
1910
17 days
1911
11 days
1912
14 days
1913
18 days
1914
15 days
1915
14 days
1916
21 days
1917
22 days
1918
19 days
1919
19 days
1920
13 days
1921
17 days
1922
25 days
1923
20 days
1924
36 days
1925
16 days
1926
17 days
1927
15 days
1928
16 days
1929
17 days
1930
26 days
1931
18 days
1932
20 days
1933
15 days
1934
18 days
1935
19 days
1936
13 days
1937
9 days
1938
13 days
1939
25 days
1940
17 days
1941
19 days
1942
20 days
1943
24 days
1944
21 days
1945
15 days
1948
10 days
1949
12 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
47 years with a frost
Across 47 years with a frost, the median last spring frost at Williamsport falls on 27 April and the median first autumn frost on 14 October, which leaves a median of 170 days between them.
Fitted over all years, the growing season changes by -5.3 days per decade at this station.
Frost dates and growing season at Williamsport
Measure
Median, all years
Earliest period
Recent period (1913 to 1943)
Recent against earliest
Fitted trend
Last spring frost
27 April
n/a
29 April
n/a
+4.2 days per decade
First autumn frost
14 October
n/a
14 October
n/a
-1.0 days per decade
Growing days
170 days
n/a
168 days
n/a
-5.3 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
43 years, 1896 to 1944
A day with at least 64.6 mm (2.5 in) of rain is expected about once in 2 years. A day with at least 127.5 mm (5.0 in) of rain is expected about once in 100 years.
Rainfall return levels at Williamsport: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
64.6 mm (2.5 in)
5 years
83.4 mm (3.3 in)
10 years
95.0 mm (3.7 in)
25 years
108.8 mm (4.3 in)
50 years
118.4 mm (4.7 in)
Longer than the 43 years of record
100 years
127.5 mm (5.0 in)
Longer than the 43 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, 43 years of values from 1896 to 1944.
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: 132.6 mm (5.2 in) in 1933; 100.3 mm (3.9 in) in 1938; 99.1 mm (3.9 in) in 1924.
Station Changes
No change in the annual mean temperature of this station was found against its neighbours.
Download the Data
Data for Williamsport standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Williamsport 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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.