Frost history / Plentywood, MT
Plentywood, MT: frost dates by year
Last spring and first fall frost at NOAA station USC00246586, 1985 to 2022, measured from daily minimum temperatures.
Elevation 2,048 ft, 48.775, -104.567. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 18 | Sep 17 |
| Earliest | Apr 27 (2018) | Aug 21 (2000) |
| Latest | Jun 24 (2004) | Oct 7 (2022) |
| Trend | 0.7 days later per decade | 2.0 days later per decade |
| Years with data | 30 | 29 |
At 28°F (hard freeze) the median last spring date is May 14 and the median first fall date is Sep 22.
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 |
|---|---|---|---|---|
| 2022 | Jun 4 | Oct 7 | May 2 | Oct 7 |
| 2021 | May 14 | Sep 22 | May 12 | Oct 15 |
| 2020 | May 13 | Sep 8 | May 12 | Sep 8 |
| 2019 | May 28 | Oct 1 | May 13 | Oct 3 |
| 2018 | Apr 27 | Sep 5 | Apr 25 | Sep 22 |
| 2017 | May 20 | Sep 23 | May 20 | Sep 26 |
| 2016 | May 16 | Sep 13 | May 16 | Sep 13 |
| 2015 | May 21 | Sep 29 | May 21 | Oct 16 |
| 2014 | May 17 | Sep 11 | May 15 | Sep 12 |
| 2013 | May 12 | Sep 20 | May 12 | Sep 20 |
| 2012 | no data | Sep 17 | no data | Oct 5 |
| 2005 | May 15 | no data | May 14 | no data |
| 2004 | Jun 24 | no data | May 16 | no data |
| 2003 | May 22 | Sep 15 | May 22 | Sep 22 |
| 2002 | May 26 | Sep 19 | May 25 | Sep 22 |
| 2001 | Jun 2 | Sep 9 | May 24 | Sep 10 |
| 2000 | Jun 18 | Aug 21 | Jun 2 | Sep 22 |
| 1999 | May 17 | Sep 9 | Apr 24 | Sep 10 |
| 1998 | Jun 4 | no data | Jun 4 | no data |
| 1997 | May 20 | Sep 17 | May 20 | Sep 20 |
| 1996 | May 13 | Sep 11 | May 12 | Sep 24 |
| 1995 | May 25 | Sep 19 | May 1 | Sep 21 |
| 1994 | May 9 | Sep 22 | May 1 | Sep 22 |
| 1993 | May 19 | Sep 14 | May 18 | Sep 14 |
| 1992 | May 25 | Sep 10 | May 25 | Sep 10 |
| 1991 | May 6 | Sep 18 | May 6 | Sep 19 |
| 1990 | May 17 | Sep 29 | May 14 | Sep 29 |
| 1989 | May 6 | Sep 10 | May 6 | Sep 10 |
| 1988 | May 4 | Sep 19 | May 4 | Oct 3 |
| 1987 | May 20 | Sep 9 | Apr 20 | Oct 7 |
| 1986 | May 17 | Sep 6 | May 17 | Oct 9 |
| 1985 | no data | Sep 20 | no data | Sep 24 |
"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.