Frost history / Clear Sky, AK
Clear Sky, AK: frost dates by year
Last spring and first fall frost at NOAA station USC00502015, 2010 to 2020, measured from daily minimum temperatures.
Elevation 646 ft, 64.245, -149.183. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Jun 4 | Aug 20 |
| Earliest | May 19 (2020) | Aug 5 (2012) |
| Latest | Jul 9 (2012) | Sep 2 (2017) |
| Trend | 0.9 days later per decade | 3.1 days later per decade |
| Years with data | 11 | 10 |
At 28°F (hard freeze) the median last spring date is May 17 and the median first fall date is Sep 1.
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 19 | Aug 18 | May 18 | Sep 6 |
| 2019 | Jun 4 | Aug 19 | May 7 | Aug 19 |
| 2018 | Jun 13 | Aug 9 | May 17 | Sep 8 |
| 2017 | Jun 14 | Sep 2 | May 12 | Sep 2 |
| 2016 | Jun 4 | Aug 29 | May 19 | Aug 31 |
| 2015 | Jun 2 | Aug 30 | May 13 | Sep 2 |
| 2014 | Jun 12 | Aug 22 | May 24 | Aug 30 |
| 2013 | May 20 | no data | May 20 | no data |
| 2012 | Jul 9 | Aug 5 | May 18 | Aug 22 |
| 2011 | May 21 | Aug 12 | May 13 | Sep 16 |
| 2010 | May 21 | Aug 26 | May 14 | Aug 26 |
"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.