Frost history / Wapiti 1WSW, WY
Wapiti 1WSW, WY: frost dates by year
Last spring and first fall frost at NOAA station USC00489467, 1989 to 2017, measured from daily minimum temperatures.
Elevation 5,558 ft, 44.459, -109.416. Download the data (JSON) · NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 27 | Sep 14 |
| Earliest | May 12 (2015) | Aug 25 (1992) |
| Latest | Jun 14 (2001) | Oct 11 (1998) |
| Trend | 4.6 days earlier per decade | 1.6 days earlier per decade |
| Years with data | 15 | 11 |
At 28°F (hard freeze) the median last spring date is May 11 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 |
|---|---|---|---|---|
| 2017 | May 20 | no data | Apr 29 | no data |
| 2016 | May 13 | no data | Apr 17 | no data |
| 2015 | May 12 | no data | May 11 | no data |
| 2014 | no data | Sep 4 | no data | Sep 12 |
| 2005 | May 28 | no data | May 13 | no data |
| 2004 | Jun 1 | no data | May 30 | no data |
| 2003 | May 21 | Sep 14 | May 21 | Sep 18 |
| 2001 | Jun 14 | Sep 8 | May 21 | Oct 5 |
| 2000 | Jun 2 | Sep 20 | Apr 30 | Sep 22 |
| 1999 | May 18 | Sep 14 | May 12 | Sep 27 |
| 1998 | no data | Oct 11 | no data | Oct 11 |
| 1996 | May 22 | no data | May 6 | no data |
| 1994 | Jun 9 | no data | Apr 30 | no data |
| 1993 | Jun 5 | Aug 27 | Apr 28 | Sep 14 |
| 1992 | May 13 | Aug 25 | May 13 | Aug 25 |
| 1991 | May 28 | Sep 18 | May 5 | Oct 4 |
| 1990 | May 27 | Oct 1 | May 26 | Oct 2 |
| 1989 | no data | Sep 10 | no data | Sep 11 |
"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 1991–2020 frost probabilities.