Frost history / St. Mary 1 Ssw, MT
St. Mary 1 Ssw, MT: frost dates by year
Last spring and first fall frost at NOAA station USW00004130, 2004 to 2024, measured from daily minimum temperatures.
Elevation 4,555 ft, 48.741, -113.433. Download the data (JSON) · NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Jun 5 | Sep 5 |
| Earliest | May 15 (2016) | Aug 16 (2012) |
| Latest | Jun 26 (2022) | Sep 26 (2013) |
| Trend | little change (less than half a day per decade) | 1.3 days later per decade |
| Years with data | 20 | 21 |
At 28°F (hard freeze) the median last spring date is May 10 and the median first fall date is Sep 29.
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 | Jun 20 | Sep 20 | May 4 | Sep 30 |
| 2023 | Jun 22 | Sep 20 | May 9 | Oct 6 |
| 2022 | Jun 26 | Sep 9 | May 22 | Sep 21 |
| 2021 | May 30 | Aug 24 | May 21 | Oct 7 |
| 2020 | May 15 | Sep 7 | May 9 | Oct 16 |
| 2019 | May 29 | Aug 27 | May 5 | Sep 28 |
| 2018 | Jun 5 | Aug 27 | Apr 27 | Sep 20 |
| 2017 | May 26 | Sep 5 | Apr 22 | Sep 24 |
| 2016 | May 15 | Aug 25 | May 11 | Sep 12 |
| 2015 | no data | Aug 23 | no data | Sep 28 |
| 2014 | Jun 8 | Sep 4 | May 12 | Sep 11 |
| 2013 | Jun 4 | Sep 26 | May 6 | Oct 3 |
| 2012 | May 28 | Aug 16 | May 3 | Sep 12 |
| 2011 | May 31 | Aug 20 | May 18 | Sep 29 |
| 2010 | Jun 19 | Aug 28 | May 24 | Oct 16 |
| 2009 | Jun 9 | Sep 11 | May 10 | Oct 7 |
| 2008 | Jun 15 | Sep 7 | May 10 | Oct 9 |
| 2007 | Jun 15 | Sep 13 | May 26 | Sep 13 |
| 2006 | May 31 | Sep 1 | May 14 | Oct 7 |
| 2005 | May 30 | Sep 6 | May 24 | Sep 23 |
| 2004 | Jun 20 | Sep 10 | May 13 | Oct 1 |
"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.