Frost history / Denver Water Dept, CO
Denver Water Dept, CO: frost dates by year
Last spring and first fall frost at NOAA station USC00052223, 1998 to 2025, measured from daily minimum temperatures.
Elevation 5,228 ft, 39.729, -105.008. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 3 | Oct 10 |
| Earliest | Apr 16 (2012) | Sep 9 (2020) |
| Latest | May 24 (2019) | Oct 31 (2024) |
| Trend | 0.6 days earlier per decade | 3.3 days later per decade |
| Years with data | 27 | 25 |
At 28°F (hard freeze) the median last spring date is Apr 19 and the median first fall date is Oct 23.
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 | Apr 20 | Oct 19 | Apr 20 | Oct 29 |
| 2024 | Apr 28 | Oct 31 | Mar 27 | Nov 6 |
| 2023 | Apr 24 | Oct 27 | Apr 24 | Oct 28 |
| 2022 | May 22 | Oct 24 | Apr 15 | Nov 4 |
| 2021 | Apr 24 | Oct 15 | Apr 21 | Nov 13 |
| 2020 | Apr 18 | Sep 9 | Apr 18 | Oct 23 |
| 2019 | May 24 | Oct 10 | Apr 13 | Oct 10 |
| 2018 | Apr 26 | Oct 10 | Apr 8 | Oct 14 |
| 2017 | May 20 | Oct 9 | May 1 | Oct 9 |
| 2016 | May 8 | Oct 7 | May 3 | Oct 20 |
| 2015 | May 12 | Oct 24 | May 11 | Oct 28 |
| 2014 | May 15 | no data | May 13 | no data |
| 2013 | May 4 | Oct 4 | May 3 | Oct 6 |
| 2012 | Apr 16 | Oct 5 | Mar 22 | Oct 8 |
| 2011 | Apr 19 | Oct 19 | Apr 12 | Oct 26 |
| 2010 | May 13 | Oct 27 | Apr 9 | Oct 27 |
| 2009 | Apr 28 | Oct 2 | Apr 28 | Oct 9 |
| 2008 | May 14 | no data | Apr 28 | no data |
| 2007 | Apr 26 | no data | Apr 15 | no data |
| 2006 | May 11 | Oct 9 | May 10 | Oct 18 |
| 2005 | no data | Oct 10 | no data | Oct 24 |
| 2004 | May 3 | Oct 25 | Apr 12 | Oct 30 |
| 2003 | May 12 | Oct 14 | Apr 9 | Oct 25 |
| 2002 | May 24 | Oct 15 | Apr 20 | Oct 23 |
| 2001 | May 21 | Oct 6 | Apr 23 | Nov 9 |
| 2000 | Apr 17 | Sep 23 | Apr 16 | Sep 23 |
| 1999 | Apr 24 | Sep 29 | Apr 19 | Sep 29 |
| 1998 | Apr 19 | Oct 18 | Apr 18 | Oct 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.