Frost history / Potter Valley Powerhouse, CA
Potter Valley Powerhouse, CA: frost dates by year
Last spring and first fall frost at NOAA station USC00047109, 1951 to 2025, measured from daily minimum temperatures.
Elevation 1,018 ft, 39.362, -123.129. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Apr 12 | Nov 2 |
| Earliest | Feb 5 (2014) | Oct 10 (2019) |
| Latest | May 18 (1974) | Dec 1 (1997) |
| Trend | 3.7 days earlier per decade | 0.8 days earlier per decade |
| Years with data | 55 | 51 |
At 28°F (hard freeze) the median last spring date is Mar 5 and the median first fall date is Nov 20.
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 | Mar 18 | Nov 25 | Feb 12 | Dec 14 |
| 2024 | Apr 6 | Oct 29 | Jan 11 | Nov 16 |
| 2023 | Apr 5 | Oct 27 | Apr 4 | Nov 25 |
| 2022 | May 10 | Nov 3 | Mar 6 | Nov 3 |
| 2021 | Mar 23 | Oct 12 | Mar 16 | Dec 10 |
| 2020 | Apr 2 | Nov 9 | Feb 10 | Nov 9 |
| 2019 | Mar 14 | Oct 10 | Feb 22 | Oct 30 |
| 2018 | Apr 17 | Nov 6 | Mar 5 | Nov 9 |
| 2017 | no data | Nov 5 | no data | Nov 18 |
| 2016 | Feb 25 | Nov 17 | Feb 25 | Dec 6 |
| 2015 | Mar 6 | Nov 4 | Feb 24 | Nov 26 |
| 2014 | Feb 5 | no data | Feb 5 | no data |
| 2013 | Apr 16 | Nov 3 | Feb 26 | Nov 4 |
| 2012 | Apr 7 | no data | Apr 6 | no data |
| 2011 | Apr 29 | Nov 3 | Feb 27 | Nov 19 |
| 2010 | Apr 5 | Oct 27 | Mar 10 | Nov 24 |
| 2009 | no data | Oct 28 | no data | Nov 13 |
| 2008 | Apr 30 | Oct 11 | Apr 21 | Nov 21 |
| 2007 | Mar 29 | no data | Feb 3 | no data |
| 2006 | Mar 26 | Oct 29 | Mar 13 | Nov 12 |
| 2005 | Mar 30 | no data | Jan 15 | no data |
| 2004 | Apr 1 | Oct 27 | Feb 12 | Nov 20 |
| 2003 | Apr 14 | Nov 1 | Feb 10 | Nov 1 |
| 2002 | Apr 18 | Oct 30 | Mar 18 | Dec 3 |
| 2001 | Apr 14 | Nov 7 | Apr 8 | Nov 27 |
| 2000 | Mar 21 | Nov 9 | Jan 28 | Nov 10 |
| 1999 | May 16 | Nov 22 | Apr 9 | Nov 22 |
| 1998 | Apr 14 | Oct 30 | Mar 6 | Dec 4 |
| 1997 | Apr 10 | Dec 1 | Mar 4 | Dec 10 |
| 1996 | Apr 20 | Oct 20 | Mar 6 | Dec 2 |
| 1995 | Apr 21 | Oct 24 | Feb 20 | Dec 21 |
| 1994 | Mar 31 | Oct 29 | Feb 22 | Oct 31 |
| 1993 | Apr 12 | Nov 13 | Feb 27 | Nov 15 |
| 1992 | Apr 6 | no data | Feb 3 | no data |
| 1991 | Apr 12 | Oct 31 | Mar 27 | Nov 29 |
| 1990 | Mar 13 | Nov 1 | Mar 13 | Nov 23 |
| 1989 | no data | Oct 28 | no data | Nov 27 |
| 1987 | Apr 19 | Nov 15 | Mar 24 | Nov 26 |
| 1986 | no data | Nov 12 | no data | Nov 27 |
| 1985 | Mar 29 | Oct 14 | Mar 3 | Nov 12 |
| 1984 | Feb 26 | Oct 27 | Feb 22 | Dec 16 |
| 1983 | Apr 13 | Nov 8 | Jan 20 | none |
| 1982 | Apr 8 | Nov 9 | Feb 11 | Dec 11 |
| 1981 | Apr 12 | no data | Feb 1 | no data |
| 1980 | no data | Nov 12 | no data | Nov 12 |
| 1979 | Apr 19 | no data | Feb 3 | no data |
| 1978 | Apr 21 | Oct 31 | Jan 24 | Nov 12 |
| 1977 | May 7 | no data | Mar 30 | no data |
| 1976 | Apr 9 | Nov 28 | Apr 1 | Nov 28 |
| 1975 | May 4 | Oct 23 | Apr 17 | Nov 9 |
| 1974 | May 18 | Nov 2 | Mar 9 | Nov 29 |
| 1973 | Apr 18 | no data | Mar 22 | no data |
| 1972 | Apr 29 | Oct 30 | Apr 19 | Oct 30 |
| 1971 | Apr 21 | Oct 16 | Apr 21 | Oct 28 |
| 1970 | Apr 29 | Oct 26 | Feb 20 | Oct 27 |
| 1969 | Apr 25 | Nov 10 | Mar 14 | Nov 17 |
| 1968 | no data | Nov 13 | no data | Nov 28 |
| 1958 | no data | Nov 11 | no data | Nov 16 |
| 1957 | Mar 23 | no data | Mar 22 | no data |
| 1953 | May 9 | no data | Apr 8 | no data |
| 1952 | Apr 29 | Nov 2 | Mar 21 | Nov 16 |
| 1951 | Mar 31 | Nov 16 | Mar 31 | Nov 23 |
"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.