Frost history / Clam Lake 4W, WI
Clam Lake 4W, WI: frost dates by year
Last spring and first fall frost at NOAA station USC00471604, 2009 to 2025, measured from daily minimum temperatures.
Elevation 1,498 ft, 46.169, -90.981. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 18 | Sep 30 |
| Earliest | Apr 29 (2012) | Sep 10 (2020) |
| Latest | May 31 (2015) | Oct 22 (2021) |
| Trend | 2.8 days earlier per decade | 9.1 days later per decade |
| Years with data | 15 | 17 |
At 28°F (hard freeze) the median last spring date is May 8 and the median first fall date is Oct 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 | May 24 | Oct 8 | May 8 | Oct 24 |
| 2024 | May 11 | Oct 5 | Apr 25 | Oct 16 |
| 2023 | May 4 | Oct 17 | May 3 | Oct 28 |
| 2022 | May 6 | Sep 28 | May 5 | Oct 17 |
| 2021 | May 29 | Oct 22 | May 12 | Oct 22 |
| 2020 | May 14 | Sep 10 | May 14 | Oct 4 |
| 2019 | no data | Oct 12 | no data | Oct 25 |
| 2018 | May 20 | Sep 29 | May 12 | Sep 29 |
| 2017 | May 20 | Oct 10 | May 8 | Oct 28 |
| 2016 | May 18 | Oct 9 | May 15 | Oct 24 |
| 2015 | May 31 | Sep 30 | Apr 27 | Oct 17 |
| 2014 | May 17 | Sep 14 | Apr 24 | Oct 10 |
| 2013 | May 25 | Oct 14 | May 14 | Oct 20 |
| 2012 | Apr 29 | Sep 23 | Apr 28 | Sep 27 |
| 2011 | May 27 | Sep 16 | May 5 | Oct 2 |
| 2010 | May 15 | Sep 26 | May 9 | Oct 3 |
| 2009 | no data | Sep 30 | 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.