Frost history / Bullfrog Basin, UT
Bullfrog Basin, UT: frost dates by year
Last spring and first fall frost at NOAA station USC00421020, 1967 to 2025, measured from daily minimum temperatures.
Elevation 3,822 ft, 37.527, -110.717. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Apr 2 | Nov 10 |
| Earliest | Feb 23 (1978) | Oct 11 (2019) |
| Latest | Apr 29 (1972) | Dec 1 (2025) |
| Trend | 1.2 days earlier per decade | 0.5 days earlier per decade |
| Years with data | 40 | 42 |
At 28°F (hard freeze) the median last spring date is Mar 7 and the median first fall date is Nov 21.
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 | Mar 21 | Dec 1 | Mar 20 | Dec 1 |
| 2024 | Apr 8 | Nov 8 | Mar 1 | Nov 8 |
| 2023 | Apr 21 | Oct 31 | Apr 6 | Nov 13 |
| 2022 | no data | Oct 29 | no data | Nov 11 |
| 2021 | Apr 2 | no data | Mar 28 | no data |
| 2020 | Apr 15 | Oct 26 | Feb 28 | Oct 26 |
| 2019 | Mar 18 | Oct 11 | Feb 27 | Oct 30 |
| 2018 | Mar 21 | Nov 9 | Mar 7 | Nov 10 |
| 2017 | Mar 8 | Nov 18 | Mar 7 | Nov 19 |
| 2016 | Mar 25 | Nov 18 | Feb 25 | Nov 26 |
| 2015 | Apr 5 | Nov 11 | Mar 5 | Nov 22 |
| 2014 | Apr 16 | Nov 14 | Mar 21 | Nov 17 |
| 2013 | Apr 19 | Nov 6 | Mar 1 | Nov 6 |
| 2012 | Mar 21 | Nov 11 | Mar 21 | Nov 11 |
| 2011 | Apr 5 | Nov 4 | Mar 2 | Nov 27 |
| 2010 | Apr 7 | Nov 10 | Feb 24 | Nov 25 |
| 2009 | no data | Oct 30 | no data | Nov 15 |
| 2007 | Mar 7 | Nov 22 | Mar 3 | Nov 22 |
| 2006 | Mar 20 | Nov 11 | Mar 16 | Nov 29 |
| 2005 | Apr 2 | no data | Mar 16 | no data |
| 2004 | Mar 1 | Nov 2 | Feb 16 | Nov 30 |
| 2002 | Mar 20 | Nov 6 | Mar 15 | Nov 27 |
| 2001 | no data | Nov 20 | no data | Nov 26 |
| 2000 | Mar 22 | Nov 8 | Feb 28 | Nov 13 |
| 1999 | Apr 11 | Nov 19 | Feb 24 | Nov 23 |
| 1998 | no data | Nov 10 | no data | Dec 6 |
| 1997 | no data | Oct 26 | no data | Nov 15 |
| 1988 | Mar 30 | no data | Mar 28 | no data |
| 1984 | Apr 26 | no data | Mar 7 | no data |
| 1983 | Apr 8 | Nov 9 | Feb 2 | Nov 27 |
| 1982 | Mar 24 | Nov 4 | Mar 6 | Nov 14 |
| 1981 | Mar 31 | Nov 20 | Feb 27 | Nov 25 |
| 1980 | Apr 1 | Oct 24 | Mar 31 | Nov 17 |
| 1979 | Mar 12 | Nov 12 | Mar 4 | Nov 20 |
| 1978 | Feb 23 | Nov 18 | Feb 19 | Dec 3 |
| 1977 | Apr 4 | Nov 9 | Mar 30 | Nov 9 |
| 1976 | Mar 30 | Nov 23 | Mar 12 | Nov 27 |
| 1975 | Apr 17 | Oct 22 | Apr 2 | Nov 12 |
| 1974 | Apr 1 | Nov 10 | Mar 4 | Nov 30 |
| 1973 | Apr 8 | Nov 16 | Feb 21 | Nov 24 |
| 1972 | Apr 29 | Oct 30 | Apr 29 | Nov 29 |
| 1971 | Apr 2 | Oct 30 | Mar 20 | Oct 30 |
| 1970 | Apr 1 | Oct 28 | Mar 23 | Oct 28 |
| 1969 | Apr 25 | Nov 18 | Apr 6 | Nov 19 |
| 1968 | Apr 7 | Nov 18 | Feb 5 | Nov 27 |
| 1967 | no data | Nov 24 | no data | Nov 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.