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Will it freeze in Windsor in the next 7 nights?
No overnight lows at or below 32°F are forecast in Windsor during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 42°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM PST to Fri, Nov 6, 6:00 AM PST.
No nights at or below 36°F in the National Weather Service forecast for the next 7 nights.
- Tonight 42°F Above 36°F · Mostly Clear
- Fri, Nov 6 42°F Above 36°F · Mostly Clear
- Sat, Nov 7 44°F Above 36°F · Areas Of Fog
- Sun, Nov 8 44°F Above 36°F · Areas Of Fog
- Mon, Nov 9 44°F Above 36°F · Partly Cloudy then Areas Of Fog
- Tue, Nov 10 45°F Above 36°F · Areas Of Fog
- Wed, Nov 11 44°F Above 36°F · Chance Light Rain
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 December 5, from NOAA’s 1991–2020 Climate Normals at Santa Rosa Sonoma County Airport. 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 | Mar 17 · Apr 12 · May 1 | Oct 16 · Nov 3 · Nov 21 | 206 days |
| 32°F freeze | Jan 27 · Mar 2 · Apr 2 | Nov 1 · Nov 20 · Dec 10 | 262 days |
| 28°F hard freeze | Dec 20 · Jan 23 · Feb 23 | Nov 15 · Dec 5 · Jan 7 | 321 days |
Average high temperature by month
1991–2020 normals at Santa Rosa Sonoma County Airport
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, CA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Santa Rosa Sonoma County Airport (station USW00023213, elevation 114 ft), 2.7 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 |
|---|---|---|---|
| Healdsburg, CA | 6.2 mi | Feb 15 | Dec 2 |
| Santa Rosa, CA | 8.7 mi | Feb 25 | Dec 1 |
| Sebastopol, CA | 9.9 mi | Mar 20 | Nov 13 |
| Rohnert Park, CA | 15 mi | Feb 25 | Dec 1 |
| Cotati, CA | 16 mi | Feb 28 | Nov 25 |
| St. Helena, CA | 19 mi | Feb 3 | Dec 4 |
| Cloverdale, CA | 21 mi | Feb 25 | Dec 3 |
| Petaluma, CA | 23 mi | Feb 28 | Nov 25 |
| Sonoma, CA | 25 mi | Mar 2 | Nov 27 |
| Clearlake, CA | 30 mi | Apr 10 | Nov 6 |
Frequently asked questions
When is the last frost in Windsor?
On average, the last spring frost (32°F) in Windsor is around March 2. In about 1 year in 10 it comes after April 2, and in 9 years in 10 it comes after January 27.
When is the first frost in Windsor?
The first fall frost (32°F) usually arrives around November 20. There’s a 10% chance of a freeze by November 1 and a 90% chance by December 10.
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 April 12.
What growing zone is Windsor?
Windsor is in USDA Plant Hardiness Zone 9a (average annual extreme minimum temperature 20 to 25°F), based on the 2023 USDA map for ZIP code 95492. See growing zones in California.
More: all California frost dates · California growing zones · UV index today in Windsor · frost vs. freeze