Frost history / Mt Diablo Junction, CA
Mt Diablo Junction, CA: frost dates by year
Last spring and first fall frost at NOAA station USC00045915, 1952 to 2025, measured from daily minimum temperatures.
Elevation 2,170 ft, 37.879, -121.930. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Mar 26 | Nov 30 |
| Earliest | Jan 1 (2015) | Oct 19 (1990) |
| Latest | May 6 (1964) | Dec 31 (1982) |
| Trend | 3.4 days earlier per decade | little change (less than half a day per decade) |
| Years with data | 71, 2 with no freeze | 71, 15 with no freeze |
At 28°F (hard freeze) the median last spring date is Feb 17 and the median first fall date is Dec 8.
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 | Jan 12 | none | none | none |
| 2023 | Apr 4 | none | Mar 2 | none |
| 2022 | Apr 12 | Dec 2 | none | none |
| 2021 | Mar 15 | Dec 15 | none | none |
| 2020 | Mar 26 | none | none | none |
| 2019 | Mar 8 | Nov 28 | none | none |
| 2018 | Mar 25 | none | Feb 20 | none |
| 2017 | Mar 6 | none | Jan 6 | none |
| 2016 | Jan 31 | Dec 18 | none | none |
| 2015 | Jan 1 | Nov 25 | none | Dec 27 |
| 2014 | Feb 5 | Dec 25 | none | none |
| 2013 | Feb 20 | Dec 4 | Jan 13 | Dec 5 |
| 2012 | Apr 13 | Dec 19 | Apr 13 | none |
| 2011 | Apr 8 | Nov 19 | Feb 27 | none |
| 2010 | Apr 5 | Nov 24 | Feb 9 | none |
| 2009 | Apr 16 | Dec 7 | Mar 9 | Dec 8 |
| 2008 | Apr 30 | Dec 14 | Apr 24 | Dec 18 |
| 2007 | Apr 19 | Nov 30 | Apr 18 | Nov 30 |
| 2006 | Apr 18 | Nov 23 | Mar 13 | Nov 28 |
| 2005 | Apr 14 | Nov 27 | none | none |
| 2004 | Feb 19 | Nov 28 | Jan 4 | Nov 30 |
| 2003 | Apr 5 | Nov 1 | none | Dec 26 |
| 2002 | Mar 18 | Dec 18 | Jan 30 | none |
| 2001 | Apr 21 | Nov 25 | Apr 4 | Dec 4 |
| 2000 | Mar 10 | Nov 11 | none | Nov 11 |
| 1999 | Apr 28 | Dec 2 | Apr 9 | Dec 17 |
| 1998 | Mar 29 | Dec 4 | none | Dec 20 |
| 1997 | Jan 14 | Dec 24 | Jan 14 | none |
| 1996 | Feb 27 | none | none | none |
| 1995 | Apr 19 | none | Feb 15 | none |
| 1994 | Mar 23 | Nov 10 | Feb 12 | Nov 18 |
| 1993 | Feb 26 | Nov 23 | Jan 11 | none |
| 1992 | Feb 15 | Dec 18 | Jan 21 | none |
| 1991 | Mar 27 | Nov 27 | Mar 26 | none |
| 1990 | Mar 13 | Oct 19 | Feb 19 | Dec 18 |
| 1989 | Apr 25 | none | Mar 3 | none |
| 1988 | no data | Dec 21 | no data | Dec 25 |
| 1987 | Mar 22 | no data | Jan 16 | no data |
| 1986 | Mar 14 | no data | none | no data |
| 1985 | Mar 28 | Nov 11 | none | Nov 13 |
| 1984 | Feb 21 | Nov 26 | Feb 21 | none |
| 1983 | Jan 20 | Dec 4 | none | none |
| 1982 | Mar 30 | Dec 31 | Jan 22 | none |
| 1981 | none | none | none | none |
| 1980 | Mar 13 | no data | Jan 29 | no data |
| 1979 | Mar 2 | none | none | none |
| 1978 | none | Nov 11 | none | Dec 7 |
| 1977 | Mar 14 | Nov 19 | none | none |
| 1976 | Apr 1 | none | Mar 2 | none |
| 1975 | May 4 | Nov 29 | Apr 1 | none |
| 1974 | Mar 11 | Dec 21 | Jan 12 | none |
| 1973 | Mar 22 | none | none | none |
| 1972 | Apr 14 | Nov 29 | Jan 27 | Nov 30 |
| 1971 | Apr 21 | Oct 28 | none | none |
| 1970 | Apr 28 | Dec 18 | none | none |
| 1969 | Mar 10 | none | Jan 31 | none |
| 1968 | Jan 29 | Dec 19 | none | Dec 20 |
| 1967 | Apr 22 | Nov 30 | none | Dec 13 |
| 1966 | Mar 4 | none | Mar 3 | none |
| 1965 | Apr 10 | Dec 16 | Jan 2 | none |
| 1964 | May 6 | Nov 13 | none | Dec 31 |
| 1963 | Apr 24 | Dec 12 | Jan 27 | none |
| 1962 | Mar 10 | Dec 24 | Feb 28 | none |
| 1961 | Apr 19 | Dec 9 | none | none |
| 1960 | Apr 22 | Nov 14 | Jan 4 | none |
| 1959 | Feb 22 | Dec 31 | none | none |
| 1958 | no data | Nov 15 | no data | none |
| 1957 | Apr 1 | Nov 23 | Jan 30 | none |
| 1956 | Mar 28 | Dec 7 | Mar 28 | none |
| 1955 | Apr 14 | Nov 14 | Feb 19 | none |
| 1954 | Mar 19 | Dec 26 | none | none |
| 1953 | Apr 10 | Nov 20 | none | none |
| 1952 | no data | Nov 24 | no data | none |
"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.