Frost history / Powder River #2, WY
Powder River #2, WY: frost dates by year
Last spring and first fall frost at NOAA station USC00487376, 1965 to 2008, measured from daily minimum temperatures.
Elevation 5,700 ft, 43.035, -106.988. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 30 | Sep 14 |
| Earliest | May 4 (1994) | Aug 16 (1975) |
| Latest | Jul 4 (1972) | Oct 10 (2006) |
| Trend | 4.0 days earlier per decade | 1.0 days later per decade |
| Years with data | 28 | 31 |
At 28°F (hard freeze) the median last spring date is May 12 and the median first fall date is Sep 20.
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 |
|---|---|---|---|---|
| 2008 | May 25 | Sep 3 | May 3 | Sep 24 |
| 2007 | May 24 | Sep 14 | May 4 | Oct 15 |
| 2006 | May 30 | Oct 10 | May 10 | Oct 10 |
| 2005 | Jun 1 | Sep 13 | May 12 | Sep 13 |
| 2004 | Jun 2 | Sep 22 | May 29 | Oct 8 |
| 2003 | May 20 | Sep 14 | May 20 | Sep 18 |
| 2002 | May 25 | no data | May 12 | no data |
| 2000 | May 17 | Sep 7 | May 17 | Sep 22 |
| 1999 | no data | Sep 12 | no data | Sep 13 |
| 1998 | May 25 | no data | May 5 | no data |
| 1995 | Jun 9 | Sep 20 | May 14 | Sep 20 |
| 1994 | May 4 | Sep 21 | May 3 | Sep 22 |
| 1993 | May 25 | no data | May 2 | no data |
| 1992 | Jun 20 | Sep 8 | May 2 | Sep 14 |
| 1991 | May 6 | Sep 16 | May 5 | Sep 18 |
| 1990 | May 26 | Sep 30 | May 17 | Oct 3 |
| 1989 | May 31 | Sep 11 | May 26 | Sep 11 |
| 1988 | no data | Sep 19 | no data | Oct 7 |
| 1982 | May 31 | no data | May 30 | no data |
| 1981 | May 12 | Sep 27 | May 12 | Oct 8 |
| 1980 | May 15 | Sep 16 | May 14 | Sep 22 |
| 1979 | Jun 10 | no data | May 12 | no data |
| 1978 | Jun 2 | Sep 13 | May 9 | Sep 13 |
| 1977 | no data | Aug 31 | no data | Oct 1 |
| 1976 | Jun 14 | Aug 27 | Jun 14 | Aug 27 |
| 1975 | Jun 17 | Aug 16 | May 26 | Aug 24 |
| 1974 | Jun 8 | Aug 31 | May 11 | Sep 12 |
| 1973 | Jun 18 | Sep 15 | May 12 | Sep 15 |
| 1972 | Jul 4 | Sep 20 | May 2 | Sep 20 |
| 1971 | no data | Sep 14 | no data | Sep 15 |
| 1970 | no data | Sep 9 | no data | Sep 12 |
| 1969 | no data | Sep 24 | no data | Sep 25 |
| 1968 | no data | Sep 2 | no data | Sep 2 |
| 1967 | May 20 | Oct 7 | May 16 | Oct 14 |
| 1966 | Jun 5 | Sep 30 | May 23 | Oct 3 |
| 1965 | no data | Sep 5 | no data | Sep 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.