Sonoma, CA: frost dates by year

Last spring and first fall frost at NOAA station USC00048351, 1952 to 2025, measured from daily minimum temperatures.

Elevation 97 ft, 38.299, -122.462. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Mar 17	Nov 20
Earliest	Jan 2 (2016)	Oct 4 (1954)
Latest	Jun 12 (1952)	Dec 29 (2025)
Trend	8.6 days earlier per decade	4.8 days later per decade
Years with data	70, 1 with no freeze	70, 3 with no freeze

At 28°F (hard freeze) the median last spring date is Feb 11 and the median first fall date is Dec 1.

The trend is a straight-line fit through the years with a freeze. A positive spring trend means the last frost now comes later. Short or patchy records give noisy trends.

Chart

Last spring frost (32°F)

First fall frost (32°F)

Dots are single years. The gray line is the median, the green line the fitted trend.

Year by year

Year	Last spring 32°F	First fall 32°F	Last spring 28°F	First fall 28°F
2025	Feb 12	Dec 29	none	none
2024	Feb 8	Nov 29	none	none
2023	Mar 27	Nov 26	Feb 24	none
2022	Feb 26	Nov 20	Feb 24	none
2021	Mar 15	Dec 18	none	none
2020	Mar 26	no data	none	no data
2019	Feb 23	Nov 29	Jan 2	Nov 29
2018	Mar 18	Nov 10	Feb 24	none
2017	Mar 1	no data	Jan 6	no data
2016	Jan 2	Dec 7	none	Dec 17
2015	Jan 5	Nov 27	Jan 2	Nov 29
2014	Feb 5	Dec 27	none	none
2013	Feb 26	no data	Jan 22	no data
2012	Mar 17	Dec 13	Feb 26	Dec 19
2011	Mar 1	Nov 8	Feb 27	Dec 13
2010	no data	Nov 24	no data	Nov 24
2009	Mar 13	Nov 17	Mar 10	Dec 4
2008	Apr 7	Dec 6	Jan 21	Dec 14
2007	Mar 2	Nov 21	Jan 23	Dec 1
2006	Mar 13	Oct 29	Mar 11	Dec 18
2005	Jan 12	Nov 27	none	none
2004	Apr 17	Nov 29	Jan 4	Dec 1
2003	Feb 10	Nov 23	Feb 8	Nov 23
2002	Mar 8	none	Jan 31	none
2001	Feb 14	none	Jan 20	none
2000	Feb 24	Nov 11	Jan 6	Nov 12
1999	Apr 9	Dec 4	Jan 24	none
1998	Mar 7	Dec 4	none	Dec 5
1997	Mar 5	Dec 15	Jan 14	Dec 23
1996	Mar 8	Dec 2	Feb 26	none
1995	Feb 15	none	none	none
1994	Mar 23	Nov 11	Feb 12	Nov 23
1993	Feb 28	Nov 16	Jan 11	Nov 26
1992	Feb 4	Nov 11	Jan 13	Dec 18
1991	Feb 1	Nov 22	Jan 30	Dec 21
1990	Mar 13	Nov 24	Feb 19	Dec 3
1989	Feb 28	Nov 29	Feb 8	Dec 13
1988	Mar 13	Dec 1	Feb 5	Dec 26
1987	Mar 23	Nov 27	Feb 26	Dec 26
1986	Feb 8	Nov 27	none	none
1985	no data	Oct 12	no data	Nov 12
1984	no data	Oct 17	no data	Dec 16
1983	Apr 14	Nov 14	none	none
1982	Apr 8	Nov 10	Feb 11	Nov 12
1981	Feb 3	Nov 29	none	none
1980	no data	Nov 12	no data	Dec 9
1979	Feb 4	no data	Feb 1	no data
1978	none	Nov 12	none	Nov 12
1977	Mar 31	Nov 20	Mar 14	none
1976	Apr 28	Nov 28	Apr 2	Nov 28
1975	Apr 17	Nov 9	Jan 31	Dec 15
1974	Mar 9	Nov 9	Feb 23	Nov 29
1973	Mar 22	Nov 4	Jan 27	Nov 4
1972	Mar 31	Nov 23	Feb 1	Dec 5
1971	Apr 21	Oct 18	Mar 6	Dec 11
1970	Apr 29	Oct 27	Jan 6	Dec 20
1969	Apr 4	Nov 17	Mar 13	Nov 18
1968	Apr 21	Nov 14	Jan 28	Dec 3
1967	May 4	Nov 23	Mar 5	Dec 1
1966	Mar 20	Oct 15	Mar 17	Nov 24
1965	Apr 7	Nov 26	Jan 8	Nov 28
1964	May 15	Nov 14	Apr 24	Nov 17
1963	Apr 21	Nov 1	Jan 22	Dec 11
1962	Mar 24	Nov 29	Mar 13	Dec 25
1961	Apr 26	Oct 22	Jan 21	Nov 17
1960	Apr 24	Nov 20	Feb 27	Dec 8
1959	Mar 14	Nov 7	Feb 13	Nov 17
1958	Mar 19	Nov 12	Mar 7	Nov 17
1957	Mar 25	Nov 4	Feb 5	Nov 30
1956	Apr 3	Oct 24	Feb 18	Nov 21
1955	Apr 27	Nov 2	Mar 22	Nov 15
1954	Apr 10	Oct 4	Mar 17	Nov 30
1953	Apr 12	Oct 24	Apr 8	Dec 23
1952	Jun 12	Nov 1	May 5	Nov 17

"none" means the station recorded no freeze at that threshold in that half of the year. "no data" means more than 10% of the season's daily readings were missing. Years with no usable data are left out. See the methodology for the rules, and the ZIP lookup for 1991 to 2020 frost probabilities.