Frost history / Dayton, WY
Dayton, WY: frost dates by year
Last spring and first fall frost at NOAA station USC00482399, 2007 to 2025, measured from daily minimum temperatures.
Elevation 3,920 ft, 44.877, -107.263. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 24 | Sep 11 |
| Earliest | Apr 25 (2023) | Aug 23 (2015) |
| Latest | Jul 27 (2022) | Oct 14 (2023) |
| Trend | 4.1 days earlier per decade | 5.1 days later per decade |
| Years with data | 15 | 16 |
At 28°F (hard freeze) the median last spring date is May 8 and the median first fall date is Oct 1.
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 | May 21 | Sep 5 | May 7 | Oct 7 |
| 2023 | Apr 25 | Oct 14 | Apr 22 | Oct 26 |
| 2022 | Jul 27 | Aug 27 | May 22 | Aug 27 |
| 2021 | May 23 | Sep 16 | May 11 | Sep 29 |
| 2020 | May 12 | Sep 8 | May 8 | Sep 8 |
| 2019 | Jun 10 | Oct 1 | May 11 | Oct 3 |
| 2018 | May 29 | Sep 21 | Apr 26 | Sep 26 |
| 2017 | May 21 | Sep 17 | May 21 | Oct 3 |
| 2016 | May 24 | Oct 6 | May 12 | Oct 6 |
| 2015 | May 22 | Aug 23 | Apr 29 | Oct 16 |
| 2014 | no data | Sep 11 | no data | Sep 12 |
| 2013 | Jun 5 | Sep 28 | Apr 25 | Oct 5 |
| 2012 | May 29 | Sep 12 | May 12 | Oct 4 |
| 2011 | no data | Sep 4 | no data | Sep 21 |
| 2009 | Jun 8 | no data | Jun 8 | no data |
| 2008 | Jun 12 | Sep 7 | May 2 | Sep 13 |
| 2007 | May 24 | Sep 9 | Apr 21 | Sep 14 |
"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.