Frost history / Castlewood #2, SD
Castlewood #2, SD: frost dates by year
Last spring and first fall frost at NOAA station USC00391520, 2012 to 2025, measured from daily minimum temperatures.
Elevation 1,689 ft, 44.727, -97.029. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 13 | Oct 5 |
| Earliest | Apr 24 (2012) | Sep 7 (2025) |
| Latest | May 22 (2022) | Oct 16 (2021) |
| Trend | 1.1 days earlier per decade | 7.9 days earlier per decade |
| Years with data | 13 | 14 |
At 28°F (hard freeze) the median last spring date is May 4 and the median first fall date is Oct 9.
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 30 | Sep 7 | Apr 22 | Oct 22 |
| 2024 | Apr 25 | Oct 4 | Apr 25 | Oct 5 |
| 2023 | May 20 | Oct 7 | May 4 | Oct 7 |
| 2022 | May 22 | Sep 28 | Apr 28 | Oct 8 |
| 2021 | May 12 | Oct 16 | May 12 | Nov 1 |
| 2020 | May 13 | Sep 10 | May 12 | Oct 4 |
| 2019 | May 11 | Oct 11 | May 11 | Oct 11 |
| 2018 | Apr 29 | Sep 29 | Apr 26 | Oct 4 |
| 2017 | no data | Oct 10 | no data | Oct 10 |
| 2016 | May 15 | Oct 7 | May 14 | Oct 9 |
| 2015 | May 18 | Oct 14 | Apr 22 | Oct 16 |
| 2014 | May 16 | Oct 4 | May 16 | Oct 10 |
| 2013 | May 13 | Oct 13 | May 12 | Oct 25 |
| 2012 | Apr 24 | Sep 18 | Apr 12 | 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.