Frost history / Blackfoot Fire Dept, ID
Blackfoot Fire Dept, ID: frost dates by year
Last spring and first fall frost at NOAA station USC00100915, 1951 to 2021, measured from daily minimum temperatures.
Elevation 4,499 ft, 43.192, -112.345. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 19 | Sep 22 |
| Earliest | Apr 17 (2015) | Aug 10 (1985) |
| Latest | Jun 25 (1966) | Oct 28 (2015) |
| Trend | 2.1 days earlier per decade | 2.5 days later per decade |
| Years with data | 40 | 46 |
At 28°F (hard freeze) the median last spring date is May 1 and the median first fall date is Oct 7.
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 |
|---|---|---|---|---|
| 2021 | May 9 | no data | Apr 23 | no data |
| 2020 | May 23 | Oct 22 | Apr 17 | Oct 23 |
| 2019 | May 3 | Oct 1 | May 1 | Oct 10 |
| 2018 | Apr 25 | Oct 14 | Apr 18 | Oct 14 |
| 2017 | May 18 | Oct 3 | May 18 | Oct 9 |
| 2016 | May 11 | Oct 12 | Apr 1 | Oct 12 |
| 2015 | Apr 17 | Oct 28 | Apr 7 | Nov 6 |
| 2014 | no data | Sep 12 | no data | Oct 28 |
| 2013 | May 2 | Oct 5 | May 2 | Oct 5 |
| 2012 | May 7 | Oct 4 | Apr 7 | Oct 4 |
| 2011 | May 2 | Oct 18 | Apr 24 | Oct 26 |
| 2010 | May 23 | Sep 6 | May 7 | Oct 27 |
| 2009 | no data | Oct 1 | no data | Oct 7 |
| 2008 | no data | Oct 10 | no data | Oct 13 |
| 2006 | no data | Oct 18 | no data | Oct 18 |
| 2005 | no data | Oct 5 | no data | Nov 10 |
| 2004 | Apr 29 | Sep 21 | Mar 29 | Nov 1 |
| 1995 | no data | Sep 21 | no data | Sep 21 |
| 1993 | no data | Aug 31 | no data | Sep 22 |
| 1992 | no data | Aug 24 | no data | Aug 25 |
| 1989 | Jun 21 | no data | Apr 30 | no data |
| 1988 | May 20 | Sep 12 | May 3 | Sep 28 |
| 1986 | no data | Sep 21 | no data | Oct 12 |
| 1985 | no data | Aug 10 | no data | Sep 28 |
| 1984 | May 17 | Sep 25 | Apr 30 | Sep 25 |
| 1983 | May 17 | no data | May 13 | no data |
| 1982 | Jun 4 | no data | May 7 | no data |
| 1980 | May 27 | no data | Apr 16 | no data |
| 1978 | May 31 | no data | May 31 | no data |
| 1977 | no data | Oct 1 | no data | Oct 2 |
| 1976 | no data | Sep 9 | no data | Oct 8 |
| 1975 | May 26 | Sep 19 | May 25 | Oct 23 |
| 1974 | Jun 8 | Sep 13 | May 16 | Oct 5 |
| 1973 | Jun 19 | Sep 17 | May 11 | Oct 3 |
| 1972 | May 26 | Sep 12 | May 12 | Sep 25 |
| 1971 | May 23 | Sep 15 | Apr 19 | Sep 17 |
| 1970 | May 31 | Sep 9 | May 14 | Sep 14 |
| 1969 | May 1 | Oct 3 | May 1 | Oct 4 |
| 1968 | May 16 | Sep 23 | May 7 | Oct 8 |
| 1967 | May 26 | Sep 13 | May 6 | Sep 13 |
| 1966 | Jun 25 | Oct 1 | May 23 | Oct 3 |
| 1964 | no data | Sep 19 | no data | Sep 27 |
| 1963 | Apr 25 | Oct 15 | Apr 25 | Oct 24 |
| 1962 | Jun 7 | Sep 8 | Apr 30 | Sep 8 |
| 1961 | May 13 | Sep 14 | May 3 | Sep 23 |
| 1960 | May 24 | Oct 13 | May 24 | Oct 14 |
| 1957 | Apr 28 | no data | Apr 27 | no data |
| 1956 | Apr 30 | Sep 22 | Apr 12 | Oct 24 |
| 1955 | May 17 | Sep 22 | Apr 27 | Oct 6 |
| 1954 | May 28 | Sep 30 | May 2 | Sep 30 |
| 1953 | May 25 | Oct 3 | May 12 | Oct 3 |
| 1952 | Apr 22 | Sep 14 | Apr 11 | Oct 14 |
| 1951 | Jun 2 | Sep 12 | Apr 23 | Oct 16 |
"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.