All-time weather records — Union City, CA

Record high
108.0°F
June 14, 2000
Record low
26.1°F
January 13, 2007
Wettest day
3.08 in
December 31, 2022

Climate change signal in Union City

36.3%

of Union City's all-time daily heat records were set in the last decade (133 of 366 records since 2015).

43.4%

of all-time daily cold records were set in the last decade (159 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 #
1990s
64
73
2000s
116
84
2010s
122
88
2020s
64
121

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 1996, the latest in 2026. Period of observation: 1996-2026.

Records by month

Month Hottest day Coldest day Wettest day
January 73.9°F — Jan 16, 2014 26.1°F — Jan 13, 2007 2.10 in — Jan 24, 2000
February 79.0°F — Feb 16, 2016 30.9°F — Feb 10, 2025 2.68 in — Feb 3, 1998
March 88.0°F — Mar 20, 2026 32.0°F — Mar 2, 2023 1.73 in — Mar 12, 2023
April 91.0°F — Apr 20, 2009 34.0°F — Apr 9, 1999 1.16 in — Apr 7, 2018
May 98.1°F — May 30, 2001 41.0°F — May 11, 2022 0.83 in — May 4, 2024
June 108.0°F — Jun 14, 2000 45.0°F — Jun 21, 2023 0.85 in — Jun 4, 2011
July 102.9°F — Jul 22, 2006 48.0°F — Jul 17, 2016 0.00 in — Jul 1, 1996
August 102.0°F — Aug 4, 1998 46.0°F — Aug 10, 2005 0.44 in — Aug 20, 1997
September 104.0°F — Sep 2, 2017 46.0°F — Sep 29, 2007 0.62 in — Sep 21, 2013
October 98.1°F — Oct 8, 1996 39.9°F — Oct 20, 1996 2.60 in — Oct 25, 2021
November 84.0°F — Nov 2, 1997 32.0°F — Nov 24, 2010 1.65 in — Nov 26, 1997
December 73.0°F — Dec 16, 1998 27.0°F — Dec 23, 1998 3.08 in — Dec 31, 2022

Click a month to see every daily record for that month in Union City.