Petaluma Ap, CA: frost dates by year

Last spring and first fall frost at NOAA station USC00046826, 1951 to 2025, measured from daily minimum temperatures.

Elevation 20 ft, 38.258, -122.608. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Mar 9	Nov 23
Earliest	Jan 1 (2016)	Oct 28 (1984)
Latest	May 10 (1985)	Dec 27 (2014)
Trend	4.5 days earlier per decade	little change (less than half a day per decade)
Years with data	70, 4 with no freeze	73, 3 with no freeze

At 28°F (hard freeze) the median last spring date is Feb 1 and the median first fall date is Dec 6.

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 11	none	none	none
2024	none	none	none	none
2023	Mar 27	Nov 9	Feb 1	Nov 27
2022	Mar 12	Nov 14	Feb 27	Nov 20
2021	Jan 26	Dec 11	Jan 26	none
2020	Apr 2	Nov 9	none	none
2019	Feb 23	Oct 30	Feb 19	none
2018	Mar 14	Nov 9	Feb 20	none
2017	Feb 25	Dec 6	Jan 7	Dec 13
2016	Jan 1	Dec 7	Jan 1	Dec 17
2015	Mar 3	Nov 11	none	Nov 29
2014	Feb 5	Dec 27	Jan 22	none
2013	Feb 26	Nov 24	Feb 10	Dec 3
2012	Apr 7	Nov 11	Feb 27	Dec 19
2011	Mar 1	Nov 8	Feb 27	Dec 6
2010	none	Nov 24	none	Nov 24
2009	Apr 5	Nov 15	Jan 13	Dec 6
2008	Apr 21	Dec 9	none	Dec 14
2007	Feb 27	Nov 21	Jan 24	Dec 1
2006	Mar 13	Nov 24	Feb 22	Nov 30
2005	Jan 13	Nov 27	none	Dec 6
2004	Feb 11	Nov 22	Jan 5	Nov 30
2003	Feb 10	Nov 23	Feb 9	Nov 23
2002	Mar 9	Dec 23	Jan 31	none
2001	no data	Nov 27	no data	none
2000	no data	Nov 10	no data	none
1999	no data	Dec 4	no data	none
1998	no data	Dec 5	no data	Dec 21
1997	Mar 5	Dec 23	Jan 14	none
1996	Feb 26	Dec 16	none	none
1995	Feb 15	none	none	none
1994	Mar 23	Nov 13	Feb 12	Dec 9
1993	Feb 15	Nov 16	Jan 11	Nov 24
1992	Feb 4	Nov 11	Jan 13	Dec 5
1991	Jan 31	no data	Jan 29	no data
1990	Feb 20	no data	Feb 18	no data
1989	Feb 15	Dec 11	Feb 7	none
1988	Mar 13	Dec 25	Feb 5	Dec 26
1987	Feb 27	Nov 27	Jan 16	none
1986	Feb 10	Nov 24	none	none
1985	May 10	Nov 12	May 10	Nov 13
1984	Feb 23	Oct 28	Jan 15	Dec 20
1983	no data	Dec 21	no data	none
1982	Mar 27	Nov 11	Feb 6	Dec 9
1981	none	Nov 24	none	none
1980	Feb 13	Nov 13	none	Dec 10
1979	Feb 5	Nov 20	Feb 3	Dec 11
1978	none	Nov 12	none	Nov 12
1977	Apr 9	Nov 19	Jan 9	none
1976	Apr 2	Nov 28	Mar 3	Dec 24
1975	Feb 23	Nov 12	Jan 30	Dec 15
1974	Mar 9	Nov 29	Jan 10	Dec 24
1973	Mar 18	Nov 4	Jan 7	none
1972	Apr 28	Nov 30	Feb 2	Dec 5
1971	Apr 24	Nov 3	Apr 24	Dec 18
1970	Feb 20	Dec 20	Jan 6	Dec 24
1969	Mar 11	Nov 17	Jan 31	Dec 1
1968	Mar 20	Nov 28	Jan 28	Dec 4
1967	Mar 5	Nov 26	Jan 17	Dec 1
1966	Mar 18	Nov 23	Mar 3	Dec 27
1965	Feb 24	Nov 28	Jan 1	Dec 15
1964	Apr 24	Nov 17	Feb 26	Nov 17
1963	Apr 21	Nov 21	Jan 21	Dec 11
1962	Mar 13	Dec 19	Feb 27	Dec 25
1961	Apr 19	Nov 14	Jan 5	Nov 17
1960	Apr 24	Nov 23	Jan 5	Dec 8
1959	Apr 18	Nov 2	Feb 13	Nov 2
1958	Mar 17	Nov 17	none	Nov 17
1957	Mar 23	Nov 6	Feb 5	Nov 29
1956	Mar 15	Nov 15	Feb 2	Nov 20
1955	Apr 27	Nov 15	Mar 5	none
1954	Mar 27	Nov 30	Mar 13	Nov 30
1953	Mar 2	Dec 23	none	Dec 26
1952	Feb 18	Nov 24	Jan 8	none
1951	Mar 11	Nov 24	Mar 3	Dec 9

"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.