Ash Mtn, CA: frost dates by year

Last spring and first fall frost at NOAA station USC00040343, 1951 to 2020, measured from daily minimum temperatures.

Elevation 1,708 ft, 36.491, -118.825. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Mar 17	Nov 28
Earliest	Jan 7 (1970)	Oct 29 (1971)
Latest	Apr 30 (2010)	Dec 29 (2018)
Trend	0.6 days later per decade	little change (less than half a day per decade)
Years with data	62	62, 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 19.

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

"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.