Frost history / Brookfield Wwtp, WI
Brookfield Wwtp, WI: frost dates by year
Last spring and first fall frost at NOAA station USC00471062, 2007 to 2025, measured from daily minimum temperatures.
Elevation 830 ft, 43.052, -88.177. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Apr 29 | Oct 14 |
| Earliest | Apr 15 (2016) | Oct 2 (2011) |
| Latest | May 13 (2020) | Oct 28 (2007) |
| Trend | 4.1 days later per decade | 3.5 days later per decade |
| Years with data | 16 | 19 |
At 28°F (hard freeze) the median last spring date is Apr 22 and the median first fall date is Oct 26.
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 9 | Oct 24 | Apr 16 | Oct 24 |
| 2024 | Apr 26 | Oct 16 | Apr 26 | Nov 2 |
| 2023 | Apr 27 | Oct 17 | Apr 24 | Oct 30 |
| 2022 | no data | Oct 8 | no data | Oct 27 |
| 2021 | May 12 | Oct 22 | Apr 22 | Nov 3 |
| 2020 | May 13 | Oct 5 | May 10 | Oct 24 |
| 2019 | Apr 29 | Oct 14 | Apr 28 | Oct 26 |
| 2018 | May 1 | Oct 13 | Apr 29 | Oct 18 |
| 2017 | May 8 | Oct 26 | Apr 1 | Nov 6 |
| 2016 | Apr 15 | Oct 14 | Apr 12 | Nov 12 |
| 2015 | Apr 28 | Oct 17 | Apr 25 | Oct 17 |
| 2014 | Apr 23 | Oct 11 | Apr 23 | Oct 22 |
| 2013 | May 13 | Oct 20 | Apr 21 | Oct 23 |
| 2012 | Apr 29 | Oct 12 | Apr 27 | Oct 12 |
| 2011 | Apr 21 | Oct 2 | Apr 21 | Oct 28 |
| 2010 | May 10 | Oct 4 | Apr 9 | Oct 22 |
| 2009 | Apr 22 | Oct 10 | Apr 16 | Oct 10 |
| 2008 | no data | Oct 4 | no data | Oct 29 |
| 2007 | no data | Oct 28 | no data | Nov 2 |
"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.