Frost history / Mazomanie Wwtp, WI
Mazomanie Wwtp, WI: frost dates by year
Last spring and first fall frost at NOAA station USC00475189, 2003 to 2021, measured from daily minimum temperatures.
Elevation 764 ft, 43.171, -89.820. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 8 | Oct 5 |
| Earliest | Apr 15 (2015) | Sep 19 (2012) |
| Latest | Jun 21 (2003) | Oct 23 (2021) |
| Trend | 9.3 days earlier per decade | 6.1 days later per decade |
| Years with data | 14 | 16 |
At 28°F (hard freeze) the median last spring date is Apr 18 and the median first fall date is Oct 16.
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 |
|---|---|---|---|---|
| 2021 | no data | Oct 23 | no data | Oct 27 |
| 2020 | May 15 | Oct 2 | May 14 | Oct 17 |
| 2019 | Apr 29 | Oct 13 | Apr 29 | Oct 15 |
| 2018 | no data | Sep 30 | no data | Oct 13 |
| 2017 | May 5 | no data | Apr 8 | no data |
| 2016 | May 16 | Oct 14 | Apr 13 | Nov 19 |
| 2015 | Apr 15 | Oct 17 | Apr 5 | Oct 17 |
| 2014 | Apr 23 | no data | Apr 23 | no data |
| 2013 | May 13 | Oct 19 | Apr 20 | Oct 19 |
| 2012 | no data | Sep 19 | no data | Sep 24 |
| 2011 | May 17 | Oct 1 | May 5 | Oct 21 |
| 2010 | May 9 | Oct 3 | Apr 10 | Oct 19 |
| 2009 | no data | Oct 10 | no data | Oct 11 |
| 2008 | no data | Oct 4 | no data | Oct 4 |
| 2007 | Apr 21 | no data | Apr 17 | no data |
| 2006 | May 6 | Oct 6 | Apr 9 | Oct 14 |
| 2005 | May 13 | Oct 8 | May 13 | Oct 22 |
| 2004 | May 4 | Sep 27 | Apr 14 | Oct 3 |
| 2003 | Jun 21 | Oct 2 | Jun 21 | Oct 3 |
"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.