Frost history / Williams Fork Dam, CO
Williams Fork Dam, CO: frost dates by year
Last spring and first fall frost at NOAA station USC00059096, 1982 to 2025, measured from daily minimum temperatures.
Elevation 7,618 ft, 40.038, -106.204. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Jun 20 | Sep 8 |
| Earliest | May 24 (2018) | Aug 1 (1995) |
| Latest | Jul 8 (1994) | Sep 22 (1998) |
| Trend | 2.7 days earlier per decade | 3.1 days later per decade |
| Years with data | 40 | 44 |
At 28°F (hard freeze) the median last spring date is Jun 1 and the median first fall date is Sep 17.
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 | Jun 23 | Sep 15 | May 22 | Sep 18 |
| 2024 | Jun 18 | Sep 14 | May 22 | Sep 18 |
| 2023 | Jun 25 | Sep 8 | May 9 | Sep 23 |
| 2022 | Jun 21 | Sep 11 | May 31 | Sep 11 |
| 2021 | Jun 11 | Sep 5 | May 28 | Sep 21 |
| 2020 | Jul 1 | Sep 2 | May 26 | Sep 9 |
| 2019 | Jun 23 | Sep 13 | Jun 10 | Sep 21 |
| 2018 | May 24 | Sep 21 | May 5 | Sep 21 |
| 2017 | Jun 14 | Sep 17 | May 28 | Sep 17 |
| 2016 | no data | Sep 8 | no data | Sep 10 |
| 2015 | May 30 | Sep 9 | May 16 | Sep 19 |
| 2014 | Jun 20 | Sep 12 | Jun 9 | Sep 15 |
| 2013 | Jun 6 | Sep 20 | Jun 1 | Sep 20 |
| 2012 | Jun 12 | Sep 14 | Jun 11 | Oct 4 |
| 2011 | Jun 10 | Sep 21 | May 31 | Sep 22 |
| 2010 | May 31 | Sep 3 | May 31 | Sep 7 |
| 2009 | Jun 8 | Aug 16 | May 17 | Sep 22 |
| 2008 | Jun 20 | Sep 4 | Jun 14 | Sep 24 |
| 2007 | Jun 10 | Sep 11 | Jun 9 | Sep 11 |
| 2006 | Jun 1 | Aug 28 | May 31 | Sep 3 |
| 2005 | Jun 14 | Aug 31 | Jun 8 | Sep 15 |
| 2004 | Jun 22 | Aug 28 | May 23 | Sep 15 |
| 2003 | Jun 26 | Sep 14 | Jun 8 | Sep 14 |
| 2002 | Jun 12 | Sep 16 | May 24 | Sep 22 |
| 2001 | Jun 16 | Sep 9 | Jun 15 | Sep 9 |
| 2000 | Jun 21 | Sep 20 | May 15 | Sep 23 |
| 1999 | Jun 11 | Sep 5 | Jun 5 | Sep 9 |
| 1998 | Jun 25 | Sep 22 | Jun 6 | Sep 27 |
| 1997 | Jul 4 | Sep 17 | May 13 | Sep 28 |
| 1996 | Jun 29 | Sep 8 | Jun 7 | Sep 18 |
| 1995 | no data | Aug 1 | no data | Sep 12 |
| 1994 | Jul 8 | Sep 5 | Jun 9 | Sep 16 |
| 1993 | Jul 7 | Sep 3 | Jun 24 | Sep 14 |
| 1992 | no data | Aug 25 | no data | Aug 27 |
| 1991 | Jul 2 | Sep 14 | May 29 | Sep 16 |
| 1990 | Jun 21 | Aug 23 | Jun 18 | Sep 22 |
| 1989 | Jul 2 | Aug 26 | Jun 23 | Sep 11 |
| 1988 | Jun 1 | Aug 31 | Jun 1 | Sep 5 |
| 1987 | Jun 25 | Aug 18 | Jun 4 | Sep 6 |
| 1986 | Jun 12 | Sep 4 | May 30 | Sep 12 |
| 1985 | Jun 28 | Aug 10 | Jun 12 | Sep 13 |
| 1984 | Jun 10 | Sep 8 | Jun 10 | Sep 25 |
| 1983 | Jul 4 | Sep 12 | Jun 14 | Sep 20 |
| 1982 | no data | Sep 15 | no data | Sep 30 |
"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.