All-time weather records — St. Helena, CA

Record high
115.0°F
July 11, 1913
Record low
-20.0°F
November 9, 1999
Wettest day
9.93 in
October 24, 2021

Climate change signal in St. Helena

9.3%

of St. Helena's all-time daily heat records were set in the last decade (34 of 366 records since 2015).

5.2%

of all-time daily cold records were set in the last decade (19 of 366 records since 2015).

If records were spread evenly across the station's history, you'd expect roughly 5% per decade. Decade-by-decade, here's where each record-breaking day was set:

Decade Heat records set # Cold records set #
1900s
5
15
1910s
48
50
1920s
51
98
1930s
62
66
1940s
17
34
1950s
27
24
1960s
26
19
1970s
24
25
1980s
19
3
1990s
30
7
2000s
15
4
2010s
29
16
2020s
13
5

Records are the all-time daily extremes that are still standing — each daily record can only be held by one year. The station's earliest hot record was set in 1907, the latest in 2022. Period of observation: 1907-2023.

Records by month

Month Hottest day Coldest day Wettest day
January 82.9°F — Jan 8, 1962 -9.0°F — Jan 27, 2002 6.83 in — Jan 21, 1967
February 86.0°F — Feb 15, 1930 18.0°F — Feb 3, 2020 5.80 in — Feb 16, 1986
March 95.0°F — Mar 17, 1914 24.1°F — Mar 3, 1951 6.40 in — Mar 9, 1995
April 98.1°F — Apr 29, 1981 27.0°F — Apr 7, 1929 3.52 in — Apr 1, 1927
May 107.1°F — May 30, 1919 30.0°F — May 23, 1979 2.00 in — May 18, 2005
June 109.9°F — Jun 18, 1920 36.0°F — Jun 2, 1923 1.61 in — Jun 2, 1967
July 115.0°F — Jul 11, 1913 26.1°F — Jul 24, 2001 1.01 in — Jul 8, 1974
August 111.9°F — Aug 28, 1915 32.0°F — Aug 9, 1978 0.73 in — Aug 20, 1997
September 113.0°F — Sep 1, 2017 33.1°F — Sep 19, 1926 3.66 in — Sep 18, 1959
October 104.0°F — Oct 3, 1917 21.9°F — Oct 2, 2019 9.93 in — Oct 24, 2021
November 93.0°F — Nov 8, 1914 -20.0°F — Nov 9, 1999 5.19 in — Nov 21, 1977
December 82.9°F — Dec 27, 1967 10.9°F — Dec 11, 1932 7.00 in — Dec 30, 1913

Click a month to see every daily record for that month in St. Helena.