Frost history / Portland Intl Ap, OR
Portland Intl Ap, OR: frost dates by year
Last spring and first fall frost at NOAA station USW00024229, 1951 to 2024, measured from daily minimum temperatures.
Elevation 19 ft, 45.591, -122.600. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Mar 25 | Nov 8 |
| Earliest | Feb 2 (2016) | Oct 8 (1985) |
| Latest | May 2 (1964) | Dec 29 (2012) |
| Trend | 3.8 days earlier per decade | 2.4 days later per decade |
| Years with data | 74 | 74 |
At 28°F (hard freeze) the median last spring date is Feb 24 and the median first fall date is Nov 28.
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 |
|---|---|---|---|---|
| 2024 | Mar 8 | Nov 30 | Jan 17 | Dec 2 |
| 2023 | Mar 16 | Oct 28 | Feb 25 | Nov 29 |
| 2022 | Mar 10 | Nov 13 | Feb 25 | Dec 15 |
| 2021 | Apr 11 | Dec 26 | Feb 14 | Dec 27 |
| 2020 | Mar 17 | Oct 26 | none | Dec 29 |
| 2019 | Mar 11 | Oct 30 | Mar 10 | Nov 29 |
| 2018 | Mar 6 | Nov 9 | Feb 23 | none |
| 2017 | Mar 19 | Dec 9 | Jan 24 | Dec 9 |
| 2016 | Feb 2 | Dec 6 | none | Dec 7 |
| 2015 | Mar 5 | Nov 21 | Jan 2 | Nov 26 |
| 2014 | Mar 22 | Nov 12 | Feb 9 | Nov 16 |
| 2013 | Mar 9 | Oct 29 | Jan 22 | Nov 21 |
| 2012 | Apr 7 | Dec 29 | Mar 7 | none |
| 2011 | Apr 8 | Nov 2 | Feb 26 | Dec 5 |
| 2010 | Mar 18 | Nov 21 | Feb 22 | Nov 23 |
| 2009 | Apr 4 | Dec 2 | Feb 27 | Dec 4 |
| 2008 | Apr 1 | Dec 5 | Jan 26 | Dec 14 |
| 2007 | Apr 3 | Nov 2 | Feb 3 | Nov 25 |
| 2006 | Mar 20 | Oct 30 | Feb 24 | Nov 29 |
| 2005 | Feb 23 | Nov 20 | Feb 17 | Nov 28 |
| 2004 | Feb 20 | Nov 5 | Jan 22 | none |
| 2003 | Mar 2 | Oct 31 | Jan 19 | Nov 1 |
| 2002 | Mar 18 | Oct 31 | Mar 2 | Nov 2 |
| 2001 | Mar 20 | Nov 7 | Feb 13 | none |
| 2000 | Mar 15 | Nov 11 | Feb 19 | Nov 11 |
| 1999 | Apr 1 | Dec 24 | Jan 5 | Dec 25 |
| 1998 | Mar 29 | Dec 9 | Jan 13 | Dec 19 |
| 1997 | Apr 5 | Dec 6 | Feb 9 | none |
| 1996 | Mar 26 | Nov 18 | Mar 2 | Nov 23 |
| 1995 | Mar 26 | Oct 30 | Mar 7 | Oct 31 |
| 1994 | Mar 7 | Nov 3 | Feb 8 | Nov 22 |
| 1993 | Mar 11 | Nov 5 | Feb 28 | Nov 11 |
| 1992 | Mar 28 | Nov 28 | none | Dec 16 |
| 1991 | Mar 20 | Oct 30 | Jan 30 | Oct 30 |
| 1990 | Mar 13 | Nov 18 | Feb 19 | Dec 7 |
| 1989 | Mar 20 | Oct 29 | Mar 3 | Dec 11 |
| 1988 | Apr 8 | Nov 30 | Feb 5 | Dec 3 |
| 1987 | Mar 28 | Nov 28 | Feb 25 | Nov 29 |
| 1986 | Feb 19 | Nov 10 | Feb 10 | Dec 9 |
| 1985 | Mar 15 | Oct 8 | Mar 7 | Nov 11 |
| 1984 | Mar 4 | Nov 21 | Jan 20 | Dec 18 |
| 1983 | Feb 5 | Nov 29 | Feb 4 | Dec 20 |
| 1982 | Apr 19 | Nov 2 | Feb 10 | Nov 25 |
| 1981 | Apr 13 | Nov 27 | Mar 5 | Nov 28 |
| 1980 | Apr 2 | Dec 6 | Feb 13 | Dec 7 |
| 1979 | Feb 21 | Nov 11 | Feb 2 | Dec 11 |
| 1978 | Mar 15 | Oct 26 | Mar 15 | Nov 10 |
| 1977 | Apr 17 | Nov 3 | Feb 14 | Nov 8 |
| 1976 | Apr 2 | Nov 20 | Mar 8 | Nov 26 |
| 1975 | Apr 8 | Nov 17 | Mar 27 | Dec 5 |
| 1974 | Mar 18 | Nov 28 | Mar 8 | Dec 23 |
| 1973 | Feb 20 | Nov 2 | Feb 13 | none |
| 1972 | Apr 22 | Oct 29 | Feb 4 | Dec 4 |
| 1971 | Apr 3 | Oct 27 | Mar 17 | Oct 28 |
| 1970 | Apr 12 | Oct 26 | Jan 11 | Nov 22 |
| 1969 | Mar 24 | Oct 14 | Mar 13 | Nov 28 |
| 1968 | Apr 22 | Nov 1 | Mar 30 | Dec 20 |
| 1967 | Apr 15 | Nov 6 | Mar 12 | Nov 21 |
| 1966 | Apr 19 | Dec 25 | Feb 16 | none |
| 1965 | Apr 6 | Nov 24 | Mar 19 | Dec 13 |
| 1964 | May 2 | Oct 23 | Feb 26 | Nov 15 |
| 1963 | Mar 17 | Oct 26 | Mar 13 | Nov 20 |
| 1962 | Mar 28 | Nov 27 | Mar 28 | Dec 1 |
| 1961 | Mar 28 | Oct 20 | Jan 27 | Nov 6 |
| 1960 | Mar 19 | Nov 7 | Mar 4 | Dec 6 |
| 1959 | Mar 20 | Oct 29 | Jan 6 | Nov 5 |
| 1958 | Mar 16 | Oct 24 | Mar 16 | Nov 16 |
| 1957 | Apr 7 | Nov 4 | Mar 17 | Nov 4 |
| 1956 | Apr 6 | Nov 19 | Mar 15 | Nov 19 |
| 1955 | Apr 25 | Nov 11 | Mar 20 | Nov 11 |
| 1954 | May 1 | Oct 27 | Mar 30 | Dec 2 |
| 1953 | Apr 2 | Nov 2 | Mar 14 | none |
| 1952 | Apr 8 | Nov 8 | Mar 21 | Nov 21 |
| 1951 | Apr 21 | Oct 30 | Mar 8 | 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.