Built 2026-10-15 (15 October 2026)

New Melones Dam HQ Weather Records (USC00046174)

Record envelope, standing records and threshold days for New Melones Dam HQ (USC00046174), California, United States, with 35 years of record.

Key Facts for New Melones Dam HQ

  • New Melones Dam HQ (USC00046174) is a weather station in California, United States at 38.00 latitude and -120.49 longitude, 293 m (960 ft) above sea level.
  • The station reports from 1992 to 2026, 35 years of record.
  • 1,464 records set at New Melones Dam HQ still stand.
  • Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
  • New Melones Dam HQ tied a daily record high maximum temperature of 37.8 C (100.0 F) on 9 October 2026 (provisional).

Provisional Records

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

About the Station

  • Location: California, United States, 38.00 latitude, -120.49 longitude.
  • Elevation: 293 m (960 ft).
  • Period of record: 1992 to 2026, 35 years.
  • Eligible elements: tmax, tmin, prcp, snow, snwd.

Daily Record Envelope and 2026

23 days at or beyond a record
Daily record high and record low at New Melones Dam HQ, with 2026 drawn through them The band shows the record high and record low for each calendar day at New Melones Dam HQ. The lines show the 2026 daily maximum and minimum. 23 days in 2026 matched or passed a record. Temperatures are in degrees Celsius. -200204060 JanFebMarAprMayJunJulAugSepOctNovDec
The band shows the record high and record low for each calendar day at New Melones Dam HQ. The lines show the 2026 daily maximum and minimum. 23 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at New Melones Dam HQ, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan23.9 C (75.0 F)-4.4 C (24.1 F)22.8 C (73.0 F)-0.6 C (30.9 F)
Feb26.7 C (80.1 F)-3.9 C (25.0 F)26.7 C (80.1 F)-0.6 C (30.9 F)
Mar32.2 C (90.0 F)-1.7 C (28.9 F)32.2 C (90.0 F)-0.6 C (30.9 F)
Apr34.4 C (93.9 F)-0.6 C (30.9 F)28.3 C (82.9 F)5.6 C (42.1 F)
May40.0 C (104.0 F)-0.6 C (30.9 F)35.0 C (95.0 F)8.3 C (46.9 F)
Jun43.9 C (111.0 F)4.4 C (39.9 F)37.8 C (100.0 F)10.0 C (50.0 F)
Jul45.6 C (114.1 F)7.2 C (45.0 F)38.9 C (102.0 F)12.2 C (54.0 F)
Aug43.3 C (109.9 F)6.1 C (43.0 F)40.0 C (104.0 F)14.4 C (57.9 F)
Sep45.6 C (114.1 F)1.1 C (34.0 F)39.4 C (102.9 F)10.6 C (51.1 F)
Oct40.6 C (105.1 F)2.2 C (36.0 F)38.9 C (102.0 F)9.4 C (48.9 F)
Nov30.0 C (86.0 F)-1.7 C (28.9 F)n/an/a
Dec24.4 C (75.9 F)-7.2 C (19.0 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at New Melones Dam HQ by the year they were set 1,464 records at New Melones Dam HQ still stand. 1999 holds the most, with 66. 0204060801992: 421993: 531994: 431995: 541996: 541997: 261998: 611999: 662000: 392001: 442002: 442003: 382004: 472005: 332006: 432007: 412008: 492009: 492010: 452011: 432012: 452013: 432014: 422015: 442016: 232017: 542018: 232019: 372020: 512021: 212022: 342023: 252024: 502025: 272026: 31199219962000200420082012201620202024
1,464 records at New Melones Dam HQ still stand. 1999 holds the most, with 66.
Standing records at New Melones Dam HQ by the year they were set
Year setStanding records
199242
199353
199443
199554
199654
199726
199861
199966
200039
200144
200244
200338
200447
200533
200643
200741
200849
200949
201045
201143
201245
201343
201442
201544
201623
201754
201823
201937
202051
202121
202234
202325
202450
202527
202631

Wettest Day of Each Month

Dec: 89.4 mm (3.5 in)
Record daily precipitation for each month at New Melones Dam HQ The wettest day on record for each calendar month at New Melones Dam HQ. The most was 89.4 mm (3.5 in) on 22 December 2015. 0255075100 Jan: 78.7 mm (3.1 in), 28 January 2021 Jan Feb: 70.1 mm (2.8 in), 3 February 2019 Feb Mar: 87.1 mm (3.4 in), 11 March 1995 Mar Apr: 51.3 mm (2.0 in), 4 April 2006 Apr May: 52.1 mm (2.1 in), 17 May 1996 May Jun: 39.1 mm (1.5 in), 16 June 1995 Jun Jul: 10.7 mm (0.4 in), 3 July 2024 Jul Aug: 9.4 mm (0.37 in), 17 August 2024 Aug Sep: 29.2 mm (1.1 in), 21 September 2005 Sep Oct: 56.4 mm (2.2 in), 29 October 2000 Oct Nov: 54.6 mm (2.1 in), 17 November 1996 Nov Dec: 89.4 mm (3.5 in), 22 December 2015 Dec
The wettest day on record for each calendar month at New Melones Dam HQ. The most was 89.4 mm (3.5 in) on 22 December 2015.
Record daily precipitation for each month at New Melones Dam HQ
MonthRecord daily precipitation (mm)Date
Jan78.7 mm (3.1 in)28 January 2021
Feb70.1 mm (2.8 in)3 February 2019
Mar87.1 mm (3.4 in)11 March 1995
Apr51.3 mm (2.0 in)4 April 2006
May52.1 mm (2.1 in)17 May 1996
Jun39.1 mm (1.5 in)16 June 1995
Jul10.7 mm (0.4 in)3 July 2024
Aug9.4 mm (0.37 in)17 August 2024
Sep29.2 mm (1.1 in)21 September 2005
Oct56.4 mm (2.2 in)29 October 2000
Nov54.6 mm (2.1 in)17 November 1996
Dec89.4 mm (3.5 in)22 December 2015

Period of Record Coverage

1992 to 2026
Days with data per year at New Melones Dam HQ 35 years of record at New Melones Dam HQ, 1992 to 2026. 2 years have data for under 90 percent of days and are left out of rankings: 1992, 2026. 1992: 306 of 366 days1993: 365 of 365 days1994: 362 of 365 days1995: 365 of 365 days1996: 363 of 366 days1997: 364 of 365 days1998: 364 of 365 days1999: 365 of 365 days2000: 365 of 366 days2001: 363 of 365 days2002: 365 of 365 days2003: 362 of 365 days2004: 365 of 366 days2005: 365 of 365 days2006: 335 of 365 days2007: 361 of 365 days2008: 362 of 366 days2009: 364 of 365 days2010: 363 of 365 days2011: 364 of 365 days2012: 363 of 366 days2013: 359 of 365 days2014: 357 of 365 days2015: 353 of 365 days2016: 365 of 366 days2017: 363 of 365 days2018: 363 of 365 days2019: 358 of 365 days2020: 358 of 366 days2021: 361 of 365 days2022: 364 of 365 days2023: 364 of 365 days2024: 362 of 366 days2025: 364 of 365 days2026: 280 of 365 days1995200020052010201520202025
35 years of record at New Melones Dam HQ, 1992 to 2026. 2 years have data for under 90 percent of days and are left out of rankings: 1992, 2026.
Days with data per year at New Melones Dam HQ
YearDays with dataShare of yearComplete
199230684%No
1993365100%Yes
199436299%Yes
1995365100%Yes
199636399%Yes
1997364100%Yes
1998364100%Yes
1999365100%Yes
2000365100%Yes
200136399%Yes
2002365100%Yes
200336299%Yes
2004365100%Yes
2005365100%Yes
200633592%Yes
200736199%Yes
200836299%Yes
2009364100%Yes
201036399%Yes
2011364100%Yes
201236399%Yes
201335998%Yes
201435798%Yes
201535397%Yes
2016365100%Yes
201736399%Yes
201836399%Yes
201935898%Yes
202035898%Yes
202136199%Yes
2022364100%Yes
2023364100%Yes
202436299%Yes
2025364100%Yes
202628077%No

Latest Records

20
Latest records at New Melones Dam HQ
DateStationRecordValueBeat old record byOld record stoodSignificance
9 October 2026New Melones Dam HQ, USdaily high max (Tie, Provisional)37.8 C (100.0 F)tie29 years2 of 100 (Routine)
8 October 2026New Melones Dam HQ, USdaily high max (Tie, Provisional)38.9 C (102.0 F)tie1 year0 of 100 (Routine)
2 October 2026New Melones Dam HQ, USdaily high min (Provisional)21.7 C (71.1 F)1.1 C (2.0 F)5 years7 of 100 (Routine)
5 September 2026New Melones Dam HQ, USdaily low max (Provisional)26.1 C (79.0 F)0.6 C (1.1 F)9 years6 of 100 (Routine)
2 September 2026New Melones Dam HQ, USdaily low min (Provisional)11.7 C (53.1 F)0.5 C (0.9 F)32 years13 of 100 (Routine)
29 August 2026New Melones Dam HQ, USdaily rain (Provisional)1.0 mm (0.04 in)1.0 mm (0.04 in)33 years14 of 100 (Routine)
28 August 2026New Melones Dam HQ, USdaily low max (Tie, Provisional)30.6 C (87.1 F)tie8 years1 of 100 (Routine)
15 August 2026New Melones Dam HQ, USdaily low max (Tie)30.0 C (86.0 F)tie27 years2 of 100 (Routine)
14 August 2026New Melones Dam HQ, USdaily low max (Tie)31.1 C (88.0 F)tie27 years2 of 100 (Routine)
27 April 2026New Melones Dam HQ, USdaily low max15.6 C (60.1 F)1.1 C (2.0 F)32 years14 of 100 (Routine)
26 April 2026New Melones Dam HQ, USdaily low max (Tie)10.6 C (51.1 F)tie32 years3 of 100 (Routine)
10 April 2026New Melones Dam HQ, USdaily high min13.3 C (55.9 F)0.5 C (0.9 F)12 years7 of 100 (Routine)
6 April 2026New Melones Dam HQ, USdaily high max28.3 C (82.9 F)2.2 C (4.0 F)19 years12 of 100 (Routine)
5 April 2026New Melones Dam HQ, USdaily high max (Tie)26.7 C (80.1 F)tie25 years2 of 100 (Routine)
30 March 2026New Melones Dam HQ, USdaily high max29.4 C (84.9 F)0.5 C (0.9 F)21 years10 of 100 (Routine)
30 March 2026New Melones Dam HQ, USdaily high min13.3 C (55.9 F)0.5 C (0.9 F)8 years6 of 100 (Routine)
25 March 2026New Melones Dam HQ, USdaily high max29.4 C (84.9 F)0.5 C (0.9 F)4 years5 of 100 (Routine)
24 March 2026New Melones Dam HQ, USdaily high max30.6 C (87.1 F)2.3 C (4.1 F)4 years9 of 100 (Routine)
23 March 2026New Melones Dam HQ, USdaily high max29.4 C (84.9 F)3.8 C (6.8 F)28 years19 of 100 (Routine)
23 March 2026New Melones Dam HQ, USdaily high min12.8 C (55.0 F)2.2 C (4.0 F)23 years16 of 100 (Routine)

Climate Trend

31 complete years, 1993 to 2025
Annual mean temperature at New Melones Dam HQ as warming stripes, 1993 to 2025 One stripe for each of 31 complete years at New Melones Dam HQ, 1993 to 2025. Blue stripes are years cooler than the station's own mean of 17.3 C (63.1 F); red stripes are warmer. The coolest year was 1998, at 15.8 C (60.4 F), and the warmest was 2014, at 18.6 C (65.4 F). The strongest colour marks a difference of 1.6 C (2.9 F). 1993: 16.4 C, -0.9 C from the station mean1994: 16.1 C, -1.2 C from the station mean1995: 17.0 C, -0.3 C from the station mean1996: 17.4 C, +0.1 C from the station mean1997: 17.4 C, +0.1 C from the station mean1998: 15.8 C, -1.5 C from the station mean1999: 16.3 C, -1.0 C from the station mean2000: 16.8 C, -0.5 C from the station mean2001: 17.6 C, +0.3 C from the station mean2003: 17.4 C, +0.1 C from the station mean2004: 17.1 C, -0.2 C from the station mean2005: 17.4 C, +0.1 C from the station mean2007: 17.0 C, -0.3 C from the station mean2008: 17.3 C, 0.0 C from the station mean2009: 17.1 C, -0.2 C from the station mean2010: 16.5 C, -0.8 C from the station mean2011: 16.5 C, -0.8 C from the station mean2012: 17.5 C, +0.3 C from the station mean2013: 17.8 C, +0.5 C from the station mean2014: 18.6 C, +1.3 C from the station mean2015: 17.7 C, +0.4 C from the station mean2016: 17.6 C, +0.3 C from the station mean2017: 17.9 C, +0.6 C from the station mean2018: 17.9 C, +0.6 C from the station mean2019: 17.3 C, 0.0 C from the station mean2020: 18.3 C, +1.0 C from the station mean2021: 17.9 C, +0.6 C from the station mean2022: 17.7 C, +0.4 C from the station mean2023: 16.8 C, -0.5 C from the station mean2024: 18.4 C, +1.1 C from the station mean2025: 17.5 C, +0.2 C from the station mean1993200020052010201520202025
One stripe for each of 31 complete years at New Melones Dam HQ, 1993 to 2025. Blue stripes are years cooler than the station's own mean of 17.3 C (63.1 F); red stripes are warmer. The coolest year was 1998, at 15.8 C (60.4 F), and the warmest was 2014, at 18.6 C (65.4 F). The strongest colour marks a difference of 1.6 C (2.9 F).
Annual mean temperature at New Melones Dam HQ as warming stripes, 1993 to 2025
YearAnnual mean temperatureDifference from the station mean
199316.4 C-0.90 C
199416.1 C-1.17 C
199517.0 C-0.25 C
199617.4 C+0.13 C
199717.4 C+0.12 C
199815.8 C-1.52 C
199916.3 C-0.99 C
200016.8 C-0.49 C
200117.6 C+0.30 C
200317.4 C+0.15 C
200417.1 C-0.15 C
200517.4 C+0.08 C
200717.0 C-0.26 C
200817.3 C+0.01 C
200917.1 C-0.16 C
201016.5 C-0.81 C
201116.5 C-0.76 C
201217.5 C+0.26 C
201317.8 C+0.53 C
201418.6 C+1.27 C
201517.7 C+0.42 C
201617.6 C+0.31 C
201717.9 C+0.59 C
201817.9 C+0.58 C
201917.3 C-0.01 C
202018.3 C+0.99 C
202117.9 C+0.57 C
202217.7 C+0.44 C
202316.8 C-0.46 C
202418.4 C+1.08 C
202517.5 C+0.24 C

The annual mean temperature here has risen by 0.4 C (0.2 to 0.6) per decade over 1993 to 2025. In Fahrenheit: 0.7 F (0.4 to 1.1) per decade. The slope is a straight line fitted to 31 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at New Melones Dam HQ
MeasurePer decade (C)Per decade (F)PeriodComplete yearsReading
Annual mean temperature0.4 C (0.2 to 0.6) per decade0.7 F (0.4 to 1.1) per decade1993 to 202531Rise
Mean daily maximum0.5 C (0.2 to 0.7) per decade0.8 F (0.4 to 1.3) per decade1993 to 202531Rise
Mean daily minimum0.3 C (0.1 to 0.6) per decade0.6 F (0.2 to 1.0) per decade1993 to 202531Rise

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

1992 to 2026
Yearly extremes at New Melones Dam HQ: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)45.6 C (114.1 F)200642.8 C (109.0 F)35
Coldest night (TNn)-7.2 C (19.0 F)2008-2.2 C (28.0 F)35
Wettest day (Rx1day)89.4 mm (3.5 in)201554.6 mm (2.1 in)35
Wettest five days (Rx5day)179.0 mm (7.0 in)2023123.5 mm (4.9 in)35
Longest dry spell (CDD)168 days2002100 days35

Hottest day (TXx)

Hottest day (TXx) at New Melones Dam HQ by year The hottest day of the year at New Melones Dam HQ, 1992 to 2026. The record is 45.6 C (114.1 F) in 2006, marked on the chart; the median year is 42.8 C (109.0 F). 3840424446200020102020Record: 45.6 C (114.1 F) in 2006
The hottest day of the year at New Melones Dam HQ, 1992 to 2026. The record is 45.6 C (114.1 F) in 2006, marked on the chart; the median year is 42.8 C (109.0 F).
Hottest day (TXx) at New Melones Dam HQ by year
YearHottest day (TXx)
199241.7 C (107.1 F)
199341.1 C (106.0 F)
199441.1 C (106.0 F)
199541.1 C (106.0 F)
199643.3 C (109.9 F)
199742.8 C (109.0 F)
199843.3 C (109.9 F)
199941.1 C (106.0 F)
200042.2 C (108.0 F)
200142.8 C (109.0 F)
200243.3 C (109.9 F)
200342.8 C (109.0 F)
200440.0 C (104.0 F)
200542.8 C (109.0 F)
200645.6 C (114.1 F)
200743.3 C (109.9 F)
200844.4 C (111.9 F)
200943.3 C (109.9 F)
201042.2 C (108.0 F)
201139.4 C (102.9 F)
201242.8 C (109.0 F)
201342.8 C (109.0 F)
201441.7 C (107.1 F)
201542.2 C (108.0 F)
201643.3 C (109.9 F)
201743.9 C (111.0 F)
201840.6 C (105.1 F)
201940.0 C (104.0 F)
202043.9 C (111.0 F)
202145.0 C (113.0 F)
202245.6 C (114.1 F)
202342.2 C (108.0 F)
202444.4 C (111.9 F)
202540.6 C (105.1 F)
202640.0 C (104.0 F)

Coldest night (TNn)

Coldest night (TNn) at New Melones Dam HQ by year The coldest night of the year at New Melones Dam HQ, 1992 to 2026. The record is -7.2 C (19.0 F) in 2008, marked on the chart; the median year is -2.2 C (28.0 F). -8-6-4-20200020102020Record: -7.2 C (19.0 F) in 2008
The coldest night of the year at New Melones Dam HQ, 1992 to 2026. The record is -7.2 C (19.0 F) in 2008, marked on the chart; the median year is -2.2 C (28.0 F).
Coldest night (TNn) at New Melones Dam HQ by year
YearColdest night (TNn)
1992-2.8 C (27.0 F)
1993-5.6 C (21.9 F)
1994-2.2 C (28.0 F)
1995-0.6 C (30.9 F)
1996-1.7 C (28.9 F)
1997-2.8 C (27.0 F)
1998-4.4 C (24.1 F)
1999-0.6 C (30.9 F)
2000-0.6 C (30.9 F)
2001-2.2 C (28.0 F)
2002-3.3 C (26.1 F)
2003-1.1 C (30.0 F)
2004-3.3 C (26.1 F)
20050.0 C (32.0 F)
2006-1.1 C (30.0 F)
2007-4.4 C (24.1 F)
2008-7.2 C (19.0 F)
2009-3.9 C (25.0 F)
2010-2.2 C (28.0 F)
2011-2.2 C (28.0 F)
2012-1.7 C (28.9 F)
2013-3.3 C (26.1 F)
2014-3.9 C (25.0 F)
2015-3.3 C (26.1 F)
2016-1.7 C (28.9 F)
2017-0.6 C (30.9 F)
2018-2.2 C (28.0 F)
2019-1.7 C (28.9 F)
2020-1.7 C (28.9 F)
2021-2.2 C (28.0 F)
2022-2.2 C (28.0 F)
2023-2.8 C (27.0 F)
2024-1.1 C (30.0 F)
2025-0.6 C (30.9 F)
2026-0.6 C (30.9 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at New Melones Dam HQ by year The wettest day of the year at New Melones Dam HQ, 1992 to 2026. The record is 89.4 mm (3.5 in) in 2015, marked on the chart; the median year is 54.6 mm (2.1 in). 20406080100200020102020Record: 89.4 mm (3.5 in) in 2015
The wettest day of the year at New Melones Dam HQ, 1992 to 2026. The record is 89.4 mm (3.5 in) in 2015, marked on the chart; the median year is 54.6 mm (2.1 in).
Wettest day (Rx1day) at New Melones Dam HQ by year
YearWettest day (Rx1day)
199258.2 mm (2.3 in)
199378.0 mm (3.1 in)
199451.3 mm (2.0 in)
199587.1 mm (3.4 in)
199654.6 mm (2.1 in)
199744.2 mm (1.7 in)
199861.5 mm (2.4 in)
199950.8 mm (2.0 in)
200056.4 mm (2.2 in)
200146.7 mm (1.8 in)
200253.1 mm (2.1 in)
200336.3 mm (1.4 in)
200452.6 mm (2.1 in)
200558.4 mm (2.3 in)
200651.3 mm (2.0 in)
200737.6 mm (1.5 in)
200846.0 mm (1.8 in)
200950.0 mm (2.0 in)
201069.1 mm (2.7 in)
201155.9 mm (2.2 in)
201264.0 mm (2.5 in)
201334.3 mm (1.4 in)
201466.8 mm (2.6 in)
201589.4 mm (3.5 in)
201650.8 mm (2.0 in)
201760.5 mm (2.4 in)
201848.5 mm (1.9 in)
201983.1 mm (3.3 in)
202066.0 mm (2.6 in)
202178.7 mm (3.1 in)
202260.7 mm (2.4 in)
202356.1 mm (2.2 in)
202442.2 mm (1.7 in)
202553.8 mm (2.1 in)
202652.1 mm (2.1 in)

Wettest five days (Rx5day)

Wettest five days (Rx5day) at New Melones Dam HQ by year The wettest five days of the year at New Melones Dam HQ, 1992 to 2026. The record is 179.0 mm (7.0 in) in 2023, marked on the chart; the median year is 123.5 mm (4.9 in). 050100150200200020102020Record: 179.0 mm (7.0 in) in 2023
The wettest five days of the year at New Melones Dam HQ, 1992 to 2026. The record is 179.0 mm (7.0 in) in 2023, marked on the chart; the median year is 123.5 mm (4.9 in).
Wettest five days (Rx5day) at New Melones Dam HQ by year
YearWettest five days (Rx5day)
1992122.1 mm (4.8 in)
1993125.7 mm (4.9 in)
199467.5 mm (2.7 in)
1995158.7 mm (6.2 in)
1996124.8 mm (4.9 in)
1997140.6 mm (5.5 in)
1998152.2 mm (6.0 in)
1999113.9 mm (4.5 in)
2000125.3 mm (4.9 in)
200184.5 mm (3.3 in)
2002131.3 mm (5.2 in)
200367.4 mm (2.7 in)
2004109.5 mm (4.3 in)
2005134.6 mm (5.3 in)
2006152.4 mm (6.0 in)
200790.2 mm (3.6 in)
200897.2 mm (3.8 in)
200996.1 mm (3.8 in)
2010155.8 mm (6.1 in)
2011146.1 mm (5.8 in)
2012107.8 mm (4.2 in)
201343.9 mm (1.7 in)
2014105.0 mm (4.1 in)
2015113.2 mm (4.5 in)
201686.6 mm (3.4 in)
2017171.8 mm (6.8 in)
2018108.0 mm (4.3 in)
2019160.7 mm (6.3 in)
2020123.5 mm (4.9 in)
2021173.2 mm (6.8 in)
2022171.5 mm (6.8 in)
2023179.0 mm (7.0 in)
202474.2 mm (2.9 in)
2025142.5 mm (5.6 in)
2026121.1 mm (4.8 in)

Longest dry spell (CDD)

Longest dry spell (CDD) at New Melones Dam HQ by year The longest dry spell of the year at New Melones Dam HQ, 1992 to 2026. The record is 168 days in 2002, marked on the chart; the median year is 100 days. 050100150200200020102020Record: 168 days in 2002
The longest dry spell of the year at New Melones Dam HQ, 1992 to 2026. The record is 168 days in 2002, marked on the chart; the median year is 100 days.
Longest dry spell (CDD) at New Melones Dam HQ by year
YearLongest dry spell (CDD)
199299 days
1993128 days
1994127 days
1995162 days
1996113 days
1997106 days
199885 days
199984 days
200081 days
200179 days
2002168 days
200383 days
2004114 days
200595 days
200676 days
2007139 days
2008128 days
200999 days
2010100 days
201197 days
201247 days
201376 days
201457 days
201559 days
2016150 days
2017102 days
2018130 days
2019112 days
2020132 days
2021164 days
202260 days
2023104 days
202458 days
2025128 days
202685 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

27 years with a frost

Across 27 years with a frost, the median last spring frost at New Melones Dam HQ falls on 28 February and the median first autumn frost on 4 December, which leaves a median of 278 days between them.

Fitted over all years, the growing season changes by +8.3 days per decade at this station.

Frost dates and growing season at New Melones Dam HQ
MeasureMedian, all yearsEarliest periodRecent period (1993 to 2025)Recent against earliestFitted trend
Last spring frost28 Februaryn/a28 Februaryn/a-3.5 days per decade
First autumn frost4 Decembern/a4 Decembern/a+4.8 days per decade
Growing days278 daysn/a278 daysn/a+8.3 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

33 years, 1993 to 2025

A day with at least 55.2 mm (2.2 in) of rain is expected about once in 2 years. A day with at least 101.3 mm (4.0 in) of rain is expected about once in 100 years.

Rainfall return levels at New Melones Dam HQ: the daily rain expected about once in a given number of years
Expected about once inA day with at leastNote
2 years55.2 mm (2.2 in)
5 years68.0 mm (2.7 in)
10 years76.2 mm (3.0 in)
25 years86.5 mm (3.4 in)
50 years94.0 mm (3.7 in)Longer than the 33 years of record
100 years101.3 mm (4.0 in)Longer than the 33 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, 33 years of values from 1993 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: 89.4 mm (3.5 in) in 2015; 87.1 mm (3.4 in) in 1995; 83.1 mm (3.3 in) in 2019.

Download the Data

  • Data for New Melones Dam HQ standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for New Melones Dam HQ 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.

Data as of . Last revised (2026-10-14).