Frost history / Bynum 4 Sse, MT
Bynum 4 Sse, MT: frost dates by year
Last spring and first fall frost at NOAA station USC00241342, 2012 to 2025, measured from daily minimum temperatures.
Elevation 4,039 ft, 47.926, -112.292. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 14 | Sep 29 |
| Earliest | Apr 28 (2017) | Sep 8 (2020) |
| Latest | May 31 (2024) | Oct 7 (2023) |
| Trend | 3.7 days later per decade | 4.9 days later per decade |
| Years with data | 13 | 13 |
At 28°F (hard freeze) the median last spring date is May 2 and the median first fall date is Oct 5.
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 | no data | Oct 5 | no data | Oct 6 |
| 2024 | May 31 | Sep 30 | May 18 | Oct 22 |
| 2023 | Apr 28 | Oct 7 | Apr 23 | Oct 24 |
| 2022 | May 23 | no data | May 22 | no data |
| 2021 | May 24 | Sep 17 | May 23 | Oct 12 |
| 2020 | May 13 | Sep 8 | Apr 20 | Oct 15 |
| 2019 | May 20 | Sep 29 | May 6 | Sep 29 |
| 2018 | May 12 | Sep 14 | Apr 18 | Sep 30 |
| 2017 | Apr 28 | Sep 22 | Apr 17 | Oct 3 |
| 2016 | May 14 | Sep 13 | Apr 17 | Oct 10 |
| 2015 | May 19 | Sep 29 | May 8 | Oct 5 |
| 2014 | May 13 | Sep 9 | Apr 28 | Sep 9 |
| 2013 | May 2 | Oct 2 | May 2 | Oct 4 |
| 2012 | May 29 | Oct 3 | May 4 | Oct 4 |
"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.