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Will it freeze in Windsor in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 26°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).
Tonight: forecast low 33°F. Frost possible.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
6 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 33°F Frost possible · Mostly Cloudy
- Fri, Nov 6 26°F Hard freeze · Mostly Clear
- Sat, Nov 7 32°F Freeze · Mostly Clear
- Sun, Nov 8 33°F Frost possible · Clear
- Mon, Nov 9 39°F Above 36°F · Mostly Clear
- Tue, Nov 10 36°F Frost possible · Partly Cloudy
- Wed, Nov 11 36°F Frost possible · Partly Cloudy
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in Windsor
The median first fall hard-freeze date (28°F) is October 18, from NOAA’s 1991–2020 Climate Normals at Arlington. This is the 50% probability date, not a forecast for this year.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | Apr 30 · May 14 · May 29 | Sep 15 · Sep 28 · Oct 8 | 135 days |
| 32°F freeze | Apr 20 · May 4 · May 18 | Sep 23 · Oct 6 · Oct 20 | 154 days |
| 28°F hard freeze | Apr 7 · Apr 22 · May 7 | Oct 3 · Oct 18 · Oct 31 | 177 days |
Average high temperature by month
1991–2020 normals at Arlington
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for Windsor, WI come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Arlington (station USC00470308, elevation 1,052 ft), 5.2 mi from Windsor. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near Windsor
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| DeForest, WI | 3.1 mi | May 4 | Oct 6 |
| Sun Prairie, WI | 5.0 mi | May 1 | Oct 10 |
| Waunakee, WI | 9.3 mi | May 1 | Oct 10 |
| Cottage Grove, WI | 11 mi | May 1 | Oct 10 |
| Madison, WI | 13 mi | May 1 | Oct 9 |
| Monona, WI | 14 mi | May 1 | Oct 9 |
| Columbus, WI | 14 mi | Apr 30 | Oct 9 |
| Middleton, WI | 15 mi | Apr 28 | Oct 15 |
| McFarland, WI | 16 mi | May 1 | Oct 9 |
| Fitchburg, WI | 19 mi | May 1 | Oct 9 |
Frequently asked questions
When is the last frost in Windsor?
On average, the last spring frost (32°F) in Windsor is around May 4. In about 1 year in 10 it comes after May 18, and in 9 years in 10 it comes after April 20.
When is the first frost in Windsor?
The first fall frost (32°F) usually arrives around October 6. There’s a 10% chance of a freeze by September 23 and a 90% chance by October 20.
Can it frost in Windsor after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after May 14.
What growing zone is Windsor?
Windsor is in USDA Plant Hardiness Zone 5a (average annual extreme minimum temperature −20 to −15°F), based on the 2023 USDA map for ZIP code 53532. See growing zones in Wisconsin.
More: all Wisconsin frost dates · Wisconsin growing zones · frost vs. freeze