Frost history / Choteau 8NE, MT
Choteau 8NE, MT: frost dates by year
Last spring and first fall frost at NOAA station USC00241738, 2010 to 2024, measured from daily minimum temperatures.
Elevation 3,741 ft, 47.864, -112.022. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 18 | Sep 21 |
| Earliest | Apr 30 (2023) | Aug 23 (2015) |
| Latest | Jun 22 (2017) | Oct 4 (2023) |
| Trend | 0.6 days earlier per decade | 7.2 days later per decade |
| Years with data | 13 | 15 |
At 28°F (hard freeze) the median last spring date is May 5 and the median first fall date is Oct 4.
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 | May 31 | Sep 30 | May 20 | Oct 13 |
| 2023 | Apr 30 | Oct 4 | Apr 23 | Oct 14 |
| 2022 | May 22 | Sep 21 | May 22 | Oct 24 |
| 2021 | May 28 | Sep 17 | May 28 | Oct 8 |
| 2020 | May 12 | Sep 8 | May 5 | Oct 15 |
| 2019 | May 9 | Sep 28 | May 5 | Sep 28 |
| 2018 | May 2 | Sep 14 | Apr 23 | Sep 30 |
| 2017 | Jun 22 | Sep 22 | Apr 20 | Sep 24 |
| 2016 | May 15 | Sep 13 | May 15 | Sep 13 |
| 2015 | May 21 | Aug 23 | May 10 | Sep 28 |
| 2014 | May 30 | Sep 9 | May 12 | Sep 12 |
| 2013 | May 6 | Sep 27 | May 5 | Sep 27 |
| 2012 | no data | Sep 12 | no data | Oct 4 |
| 2011 | May 18 | Sep 21 | Apr 30 | Oct 16 |
| 2010 | no data | Sep 23 | no data | Oct 16 |
"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.