Frost history / Great Falls 16ST, MT
Great Falls 16ST, MT: frost dates by year
Last spring and first fall frost at NOAA station USC00243749, 1953 to 2025, measured from daily minimum temperatures.
Elevation 3,505 ft, 47.488, -111.279. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 10 | Oct 2 |
| Earliest | Apr 26 (2018) | Sep 12 (2014) |
| Latest | Jun 12 (2008) | Oct 22 (1953) |
| Trend | little change (less than half a day per decade) | 1.0 days earlier per decade |
| Years with data | 16 | 18 |
At 28°F (hard freeze) the median last spring date is Apr 28 and the median first fall date is Oct 11.
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 6 | Oct 6 | Apr 24 | Oct 13 |
| 2024 | no data | Oct 4 | no data | Oct 26 |
| 2019 | May 19 | no data | May 1 | no data |
| 2018 | Apr 26 | Sep 30 | Apr 24 | Oct 1 |
| 2017 | May 3 | Sep 24 | Apr 16 | Oct 4 |
| 2016 | May 11 | Sep 13 | Apr 18 | Oct 11 |
| 2015 | May 10 | Oct 4 | Apr 27 | Oct 5 |
| 2014 | May 13 | Sep 12 | May 13 | Oct 3 |
| 2013 | May 2 | Sep 27 | May 2 | Oct 12 |
| 2012 | May 27 | Oct 5 | May 11 | Oct 5 |
| 2011 | May 2 | Oct 14 | Apr 29 | Oct 26 |
| 2010 | May 13 | Sep 17 | May 10 | Oct 16 |
| 2009 | Jun 8 | Oct 6 | May 2 | Oct 8 |
| 2008 | Jun 12 | Oct 9 | Apr 26 | Oct 9 |
| 2007 | May 15 | Sep 14 | Apr 21 | Oct 27 |
| 2006 | May 5 | Oct 12 | Apr 25 | Oct 13 |
| 1956 | May 7 | no data | May 3 | no data |
| 1955 | no data | Sep 24 | no data | Oct 22 |
| 1954 | no data | Sep 29 | no data | Oct 1 |
| 1953 | no data | Oct 22 | no data | Oct 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.