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Data as of 2025-12-31
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Built 2026-10-19 (19 October 2026)

Altamont Threshold Days by Year (USC00140190)

6 fixed thresholds counted per year at Altamont (USC00140190): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Altamont Thresholds

  • Altamont: days with 10 mm (0.39 in) or more of precipitation in 25 years, most in 2007 with 48.
  • Altamont: days with 25 mm (0.98 in) or more of precipitation in 25 years, most in 2019 with 25.
  • Altamont: days with 50 mm (1.97 in) or more of precipitation in 25 years, most in 2009 with 9.
  • Altamont: days with 10 cm (3.9 in) or more of snowfall in 9 years, most in 2010 with 3.
  • 6 fixed thresholds have at least one qualifying day at Altamont.
25 years with a qualifying day
Days with 10 mm (0.39 in) or more of precipitation per year at Altamont Days per year at Altamont with 10 mm (0.39 in) or more of precipitation, with the decade average as a line. The most was 48 in 2007. 02040601949: 321950: 272003: 402004: 352005: 312006: 252007: 482008: 452009: 402010: 292011: 272012: 282013: 392014: 252015: 372016: 312017: 372018: 332019: 442020: 452021: 362022: 242023: 362024: 352025: 37194920042007201020132016201920222025
Days per year at Altamont with 10 mm (0.39 in) or more of precipitation, with the decade average as a line. The most was 48 in 2007.
Days with 10 mm (0.39 in) or more of precipitation per year at Altamont
YearDaysDecade average
19493232
19502727
20034037.7
20043537.7
20053137.7
20062537.7
20074837.7
20084537.7
20094037.7
20102933
20112733
20122833
20133933
20142533
20153733
20163133
20173733
20183333
20194433
20204535.5
20213635.5
20222435.5
20233635.5
20243535.5
20253735.5
First to last qualifying date each year at Altamont For each year, a bar from the first to the last day at Altamont meeting 10 mm (0.39 in). 1949: 15 January 1949 to 10 December 19491950: 11 February 1950 to 2 October 19502003: 14 February 2003 to 28 December 20032004: 17 January 2004 to 7 December 20042005: 3 January 2005 to 15 November 20052006: 29 January 2006 to 30 December 20062007: 13 January 2007 to 12 December 20072008: 8 January 2008 to 27 December 20082009: 11 February 2009 to 25 December 20092010: 21 January 2010 to 31 December 20102011: 25 February 2011 to 20 December 20112012: 4 February 2012 to 12 November 20122013: 30 January 2013 to 6 November 20132014: 16 March 2014 to 15 December 20142015: 1 February 2015 to 29 December 20152016: 9 March 2016 to 8 November 20162017: 16 January 2017 to 22 October 20172018: 8 January 2018 to 31 December 20182019: 12 January 2019 to 29 December 20192020: 11 January 2020 to 30 December 20202021: 1 January 2021 to 28 December 20212022: 3 February 2022 to 13 December 20222023: 19 January 2023 to 25 December 20232024: 9 January 2024 to 19 November 20242025: 10 January 2025 to 25 November 20251949200520092013201720212025JanFebMarAprMayJunJulAugSepOctNovDec
For each year, a bar from the first to the last day at Altamont meeting 10 mm (0.39 in).
First to last qualifying date each year at Altamont
YearFirst dateLast date
19491949-01-151949-12-10
19501950-02-111950-10-02
20032003-02-142003-12-28
20042004-01-172004-12-07
20052005-01-032005-11-15
20062006-01-292006-12-30
20072007-01-132007-12-12
20082008-01-082008-12-27
20092009-02-112009-12-25
20102010-01-212010-12-31
20112011-02-252011-12-20
20122012-02-042012-11-12
20132013-01-302013-11-06
20142014-03-162014-12-15
20152015-02-012015-12-29
20162016-03-092016-11-08
20172017-01-162017-10-22
20182018-01-082018-12-31
20192019-01-122019-12-29
20202020-01-112020-12-30
20212021-01-012021-12-28
20222022-02-032022-12-13
20232023-01-192023-12-25
20242024-01-092024-11-19
20252025-01-102025-11-25

Every Fixed Threshold

Fixed thresholds at Altamont
ThresholdYears with a qualifying dayMost days in a yearYearLatest year days
10 mm (0.39 in): Days with 10 mm or more rain2548200737
25 mm (0.98 in): Days with 25 mm or more rain2525201915
50 mm (1.97 in): Days with 50 mm or more rain25920094
100 mm (3.94 in): Days with 100 mm or more rain7220141
10 cm (3.9 in): Days with 10 cm or more snowfall9320102
25 cm (9.8 in): Days with 25 cm or more snowfall1120061

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1949.

Download the Data

  • Data for Altamont 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 2026-10-17 (17 October 2026). Threshold counts are computed by this site.

Data as of . Last revised (2025-12-31).