Frost history / Wright 12W, WY
Wright 12W, WY: frost dates by year
Last spring and first fall frost at NOAA station USC00489805, 1991 to 2020, measured from daily minimum temperatures.
Elevation 5,020 ft, 43.747, -105.733. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 24 | Sep 19 |
| Earliest | May 2 (2018) | Aug 23 (2015) |
| Latest | Jun 30 (1995) | Oct 6 (1997) |
| Trend | 3.5 days earlier per decade | 1.5 days earlier per decade |
| Years with data | 26 | 30 |
At 28°F (hard freeze) the median last spring date is May 15 and the median first fall date is Oct 5.
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 |
|---|---|---|---|---|
| 2020 | May 17 | Sep 8 | May 10 | Sep 9 |
| 2019 | Jun 9 | Oct 1 | May 19 | Oct 3 |
| 2018 | May 2 | Sep 21 | May 2 | Oct 6 |
| 2017 | May 21 | Sep 5 | May 19 | Oct 3 |
| 2016 | May 24 | Oct 5 | May 17 | Oct 5 |
| 2015 | May 21 | Aug 23 | May 21 | Oct 24 |
| 2014 | May 15 | Sep 11 | May 15 | Sep 12 |
| 2013 | Jun 5 | Sep 27 | May 5 | Oct 5 |
| 2012 | May 29 | Oct 4 | May 25 | Oct 4 |
| 2011 | Jun 4 | Sep 21 | May 15 | Sep 21 |
| 2010 | May 23 | Sep 7 | May 9 | Oct 16 |
| 2009 | Jun 8 | Sep 28 | May 16 | Sep 28 |
| 2008 | May 13 | Sep 14 | May 3 | Oct 11 |
| 2007 | May 26 | Sep 10 | Apr 14 | Oct 15 |
| 2006 | no data | Sep 19 | no data | Oct 12 |
| 2005 | no data | Sep 13 | no data | Oct 5 |
| 2004 | May 30 | Oct 1 | May 14 | Oct 11 |
| 2003 | May 20 | Sep 18 | May 20 | Sep 18 |
| 2002 | Jun 11 | Sep 22 | May 24 | Oct 12 |
| 2001 | May 25 | Oct 5 | May 7 | Oct 5 |
| 2000 | Jun 17 | Sep 22 | May 13 | Sep 22 |
| 1999 | May 23 | Sep 13 | May 17 | Sep 13 |
| 1998 | Jun 6 | Oct 5 | May 8 | Oct 20 |
| 1997 | May 19 | Oct 6 | May 19 | Oct 9 |
| 1996 | May 21 | Sep 19 | May 21 | Sep 24 |
| 1995 | Jun 30 | Sep 20 | May 24 | Sep 21 |
| 1994 | no data | Sep 21 | no data | Oct 22 |
| 1993 | May 10 | Sep 13 | May 1 | Sep 14 |
| 1992 | May 28 | Sep 10 | May 2 | Sep 18 |
| 1991 | no data | Sep 18 | no data | Sep 18 |
"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.