Frost Dates for Windsor, CA
In Windsor, CA, the average last spring frost is around Mar 2 and the average first fall frost around Nov 20, for a growing season of about 262 days. For frost-tender plants, wait until Apr 2, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Santa Rosa Sonoma Co Airport, CA weather station, 3 miles away, elevation 114 ft. Frost can come earlier in low spots and valleys and later near cities and large lakes.
Frost probability by date
Chance of a 32°F frost after the spring date, or before the fall date.
| Chance | Last spring frost | First fall frost |
|---|---|---|
| 10% | Apr 2 | Nov 1 |
| 20% | Mar 24 | Nov 7 |
| 30% | Mar 14 | Nov 12 |
| 40% | Mar 7 | Nov 16 |
| 50% | Mar 2 | Nov 20 |
| 60% | Feb 26 | Nov 24 |
| 70% | Feb 21 | Nov 28 |
| 80% | Feb 11 | Dec 3 |
| 90% | Jan 27 | Dec 10 |
Light frost vs. hard freeze
Average (50%) dates for each temperature. Tender plants are damaged at 36°F; most hardy crops survive until 28°F.
| Temperature | Last in spring | First in fall |
|---|---|---|
| Light frost (36°F) | Apr 12 | Nov 3 |
| Frost / freeze (32°F) | Mar 2 | Nov 20 |
| Hard freeze (28°F) | Jan 23 | Dec 5 |
Planting calendar for Windsor
Transplant Mar 9 – Mar 23
Transplant Mar 16 – Mar 30
Transplant Mar 16 – Mar 30
Transplant Mar 9 – Mar 23
Sow or transplant Mar 9 – Mar 23
Sow or transplant Mar 9 – Mar 23
Sow or transplant Mar 16 – Mar 30
Sow or transplant Feb 2 – Feb 16
Fall sowing Sep 25 – Oct 23
Fall sowing Sep 25 – Oct 16
Fall sowing Sep 11 – Sep 25
Sow or transplant Feb 2 – Feb 16
Fall sowing Sep 11 – Oct 9
Transplant Feb 16 – Mar 2
Fall sowing Aug 28 – Sep 11
Transplant Feb 9 – Feb 23
Fall sowing Aug 28 – Sep 11
Fall sowing Aug 28 – Sep 11
Fall sowing Oct 9 – Oct 30
Fall sowing Sep 11 – Sep 25
Plant Feb 2 – Feb 16
Based on the average last frost (Mar 2) and first frost (Nov 20). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.