Frost history / Portland Wfo, OR
Portland Wfo, OR: frost dates by year
Last spring and first fall frost at NOAA station USC00356750, 1996 to 2025, measured from daily minimum temperatures.
Elevation 21 ft, 45.561, -122.538. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Mar 21 | Nov 18 |
| Earliest | Feb 20 (2004) | Oct 26 (2020) |
| Latest | Apr 15 (2022) | Dec 30 (2012) |
| Trend | 1.4 days earlier per decade | 3.3 days earlier per decade |
| Years with data | 28 | 30 |
At 28°F (hard freeze) the median last spring date is Feb 11 and the median first fall date is Dec 3.
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 6 | Dec 1 | Feb 14 | none |
| 2024 | Mar 8 | Nov 30 | Mar 7 | Dec 2 |
| 2023 | Mar 16 | Oct 28 | Feb 25 | Nov 29 |
| 2022 | Apr 15 | Nov 9 | Mar 10 | Dec 15 |
| 2021 | Apr 11 | Nov 17 | Feb 15 | Dec 27 |
| 2020 | Mar 17 | Oct 26 | Feb 4 | Dec 29 |
| 2019 | Mar 11 | Oct 28 | Mar 10 | Nov 29 |
| 2018 | Apr 3 | Nov 9 | Feb 23 | none |
| 2017 | Mar 19 | Dec 12 | Feb 3 | Dec 24 |
| 2016 | Feb 23 | Dec 6 | Jan 3 | Dec 6 |
| 2015 | Mar 5 | Nov 22 | Jan 1 | Nov 26 |
| 2014 | Mar 22 | Nov 12 | Feb 9 | Nov 16 |
| 2013 | Mar 9 | Nov 20 | Jan 21 | Nov 20 |
| 2012 | Mar 23 | Dec 30 | Mar 7 | none |
| 2011 | Apr 8 | Nov 11 | Feb 26 | Dec 5 |
| 2010 | Mar 18 | Nov 21 | none | Nov 23 |
| 2009 | Apr 4 | Dec 4 | Mar 11 | Dec 4 |
| 2008 | Apr 3 | Dec 5 | Jan 25 | Dec 14 |
| 2007 | Apr 3 | Nov 23 | Feb 3 | Dec 9 |
| 2006 | no data | Oct 30 | no data | Oct 31 |
| 2005 | Feb 21 | Nov 8 | Feb 15 | Nov 28 |
| 2004 | Feb 20 | Nov 5 | Jan 21 | none |
| 2003 | Mar 24 | Nov 1 | none | Nov 1 |
| 2002 | Mar 7 | Nov 3 | Feb 28 | none |
| 2001 | Apr 4 | Nov 6 | Feb 26 | none |
| 2000 | Mar 6 | Nov 11 | Jan 15 | Nov 12 |
| 1999 | Apr 2 | Dec 25 | Jan 5 | Dec 25 |
| 1998 | Mar 29 | Dec 6 | Jan 13 | Dec 19 |
| 1997 | Apr 5 | Dec 21 | Jan 26 | Dec 26 |
| 1996 | no data | Nov 22 | no data | 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.