Frost history / Bonneville Dam, OR
Bonneville Dam, OR: frost dates by year
Last spring and first fall frost at NOAA station USC00350897, 1951 to 2025, measured from daily minimum temperatures.
Elevation 62 ft, 45.635, -121.952. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Mar 21 | Nov 24 |
| Earliest | Jan 10 (2004) | Oct 17 (1971) |
| Latest | May 22 (1966) | Dec 31 (2025) |
| Trend | 2.9 days earlier per decade | little change (less than half a day per decade) |
| Years with data | 71, 1 with no freeze | 74 |
At 28°F (hard freeze) the median last spring date is Feb 15 and the median first fall date is Dec 7.
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 8 | Dec 31 | Feb 15 | none |
| 2024 | Mar 8 | Oct 26 | Jan 21 | none |
| 2023 | Mar 27 | Nov 24 | Feb 26 | none |
| 2022 | Apr 12 | Nov 9 | Mar 10 | Nov 20 |
| 2021 | Apr 13 | Dec 16 | Feb 13 | Dec 27 |
| 2020 | Mar 18 | Oct 26 | Jan 16 | none |
| 2019 | Mar 15 | Oct 28 | Mar 12 | Nov 30 |
| 2018 | Mar 7 | Nov 14 | Feb 24 | none |
| 2017 | Mar 18 | Nov 25 | Jan 19 | Dec 7 |
| 2016 | Jan 11 | Dec 7 | Jan 5 | Dec 8 |
| 2015 | Mar 6 | Nov 22 | Jan 3 | Nov 30 |
| 2014 | Mar 23 | Nov 12 | Mar 3 | Nov 14 |
| 2013 | Mar 23 | Nov 21 | Jan 20 | Dec 4 |
| 2012 | Mar 20 | Dec 16 | Jan 29 | none |
| 2011 | Apr 9 | Nov 21 | Feb 27 | Dec 11 |
| 2010 | Mar 19 | Nov 23 | none | Nov 24 |
| 2009 | Apr 5 | Dec 3 | Jan 28 | Dec 4 |
| 2008 | Apr 4 | Dec 6 | Jan 27 | Dec 15 |
| 2007 | no data | Nov 24 | no data | none |
| 2006 | Mar 20 | Oct 31 | Feb 24 | Nov 29 |
| 2005 | Feb 20 | Nov 28 | Jan 18 | Dec 8 |
| 2004 | Jan 10 | Nov 21 | Jan 9 | none |
| 2003 | Mar 3 | Nov 1 | Feb 3 | Dec 30 |
| 2002 | Mar 22 | Oct 31 | Mar 2 | none |
| 2001 | Apr 5 | Nov 28 | Feb 26 | none |
| 2000 | Mar 31 | Nov 11 | none | Nov 12 |
| 1999 | Apr 14 | Dec 26 | none | Dec 26 |
| 1998 | Mar 29 | Dec 6 | Jan 14 | Dec 20 |
| 1997 | no data | Dec 8 | no data | none |
| 1996 | Mar 29 | Dec 18 | Mar 26 | Dec 18 |
| 1995 | Feb 16 | Dec 9 | Feb 15 | Dec 9 |
| 1994 | Feb 28 | Nov 18 | Feb 9 | Dec 5 |
| 1993 | Mar 13 | Nov 23 | Mar 2 | Nov 23 |
| 1992 | none | Dec 4 | none | Dec 6 |
| 1991 | Jan 31 | Dec 18 | Jan 31 | none |
| 1990 | Mar 14 | Dec 19 | Feb 20 | Dec 19 |
| 1989 | Mar 5 | Dec 18 | Mar 4 | none |
| 1988 | Mar 12 | Dec 18 | Feb 3 | none |
| 1987 | no data | Dec 13 | no data | Dec 26 |
| 1986 | no data | Nov 11 | no data | none |
| 1985 | Mar 15 | no data | Feb 16 | no data |
| 1984 | Feb 17 | Nov 2 | Jan 22 | Dec 6 |
| 1983 | Feb 7 | Dec 2 | Jan 1 | Dec 19 |
| 1982 | Apr 19 | Nov 11 | Feb 11 | none |
| 1981 | Mar 7 | Dec 30 | Feb 12 | none |
| 1980 | Apr 3 | Dec 7 | Feb 15 | Dec 8 |
| 1979 | Feb 16 | Nov 23 | Feb 5 | none |
| 1978 | Feb 10 | Nov 12 | Jan 5 | Nov 12 |
| 1977 | Apr 17 | Nov 8 | Jan 29 | Nov 19 |
| 1976 | Mar 12 | Nov 28 | Mar 4 | none |
| 1975 | Apr 9 | Nov 18 | Mar 11 | none |
| 1974 | Mar 22 | Nov 17 | Mar 9 | Dec 29 |
| 1973 | Mar 23 | Nov 2 | Jan 27 | none |
| 1972 | May 1 | Dec 3 | Mar 7 | Dec 4 |
| 1971 | Mar 21 | Oct 17 | Mar 3 | Dec 8 |
| 1970 | Apr 12 | Nov 22 | Jan 17 | Nov 22 |
| 1969 | Mar 15 | Nov 30 | Mar 8 | none |
| 1968 | Apr 13 | Nov 15 | Apr 13 | Dec 20 |
| 1967 | Mar 12 | Nov 26 | none | Dec 13 |
| 1966 | May 22 | Dec 7 | Feb 16 | none |
| 1965 | Mar 26 | Nov 30 | Mar 18 | Dec 15 |
| 1964 | Apr 17 | Nov 15 | none | Dec 16 |
| 1963 | Apr 2 | Dec 1 | Feb 1 | Dec 11 |
| 1962 | Mar 28 | Nov 28 | Feb 28 | Dec 26 |
| 1961 | Mar 6 | Nov 4 | Jan 5 | Nov 12 |
| 1960 | Mar 11 | Nov 26 | Mar 5 | Dec 10 |
| 1959 | Mar 4 | Nov 6 | Jan 7 | Nov 13 |
| 1958 | Mar 15 | Nov 16 | none | Nov 27 |
| 1957 | Mar 27 | Nov 23 | Feb 24 | Nov 27 |
| 1956 | Mar 16 | Nov 19 | Mar 13 | Dec 6 |
| 1955 | Apr 26 | Nov 12 | Mar 21 | Nov 12 |
| 1954 | May 1 | Nov 30 | Mar 12 | none |
| 1953 | Apr 10 | Dec 7 | none | none |
| 1952 | Apr 8 | Nov 16 | Jan 25 | Nov 24 |
| 1951 | Apr 21 | Dec 7 | Mar 9 | 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.