Frost history / Portland-Hillsboro Ap, OR
Portland-Hillsboro Ap, OR: frost dates by year
Last spring and first fall frost at NOAA station USW00094261, 1998 to 2024, measured from daily minimum temperatures.
Elevation 204 ft, 45.541, -122.949. Download the data (JSON) · NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Apr 20 | Oct 25 |
| Earliest | Mar 17 (2016) | Sep 24 (2000) |
| Latest | May 18 (2003) | Dec 5 (2016) |
| Trend | 6.0 days earlier per decade | 8.6 days later per decade |
| Years with data | 26 | 27 |
At 28°F (hard freeze) the median last spring date is Mar 13 and the median first fall date is Nov 10.
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 | Apr 17 | Nov 15 | Mar 7 | Dec 1 |
| 2023 | Apr 20 | Oct 27 | Mar 16 | Oct 30 |
| 2022 | May 13 | Nov 8 | Mar 10 | Nov 9 |
| 2021 | Apr 12 | Oct 12 | Apr 11 | Nov 21 |
| 2020 | Apr 13 | Oct 22 | Mar 17 | Oct 25 |
| 2019 | Apr 28 | Oct 1 | Mar 11 | Oct 28 |
| 2018 | Apr 3 | Nov 7 | Mar 6 | Nov 9 |
| 2017 | Mar 19 | Oct 14 | Feb 13 | Dec 7 |
| 2016 | Mar 17 | Dec 5 | Jan 10 | Dec 6 |
| 2015 | Apr 15 | Nov 4 | Mar 4 | Nov 21 |
| 2014 | Mar 31 | Nov 12 | Feb 22 | Nov 14 |
| 2013 | May 1 | Oct 29 | Mar 4 | Nov 20 |
| 2012 | May 10 | Nov 9 | Mar 7 | Dec 30 |
| 2011 | May 1 | Oct 25 | Feb 26 | Nov 2 |
| 2010 | May 6 | Oct 17 | Feb 22 | Nov 21 |
| 2009 | Apr 24 | Oct 6 | Apr 4 | Dec 2 |
| 2008 | Apr 20 | Oct 9 | Apr 2 | Nov 27 |
| 2007 | Apr 20 | Oct 25 | Apr 3 | Oct 25 |
| 2006 | May 9 | Oct 10 | Mar 19 | Oct 30 |
| 2005 | Apr 14 | Nov 7 | Mar 15 | Nov 15 |
| 2004 | Apr 1 | Nov 4 | Feb 13 | Nov 4 |
| 2003 | May 18 | Oct 31 | Mar 24 | Oct 31 |
| 2002 | May 8 | Oct 12 | Mar 18 | Oct 25 |
| 2001 | Apr 15 | Oct 18 | Apr 7 | Nov 7 |
| 2000 | May 6 | Sep 24 | Apr 24 | Nov 10 |
| 1999 | Apr 22 | Sep 27 | Apr 9 | Oct 15 |
| 1998 | no data | Oct 16 | no data | Dec 18 |
"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 1991–2020 frost probabilities.