Frost Dates for San Rafael, CA
In San Rafael, CA, the average last spring frost is around Jan 11 and the average first fall frost around Dec 21, for a growing season of about 349 days. For frost-tender plants, wait until Feb 25, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the San Rafael Civic Ctr, CA weather station, 2 miles away, elevation 120 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% | Feb 25 | Dec 2 |
| 20% | Feb 14 | Dec 8 |
| 30% | Feb 1 | Dec 13 |
| 40% | Jan 21 | Dec 17 |
| 50% | Jan 11 | Dec 21 |
| 60% | Jan 3 | Dec 27 |
| 70% | Dec 30 | Jan 2 |
| 80% | Dec 23 | Jan 12 |
| 90% | Dec 14 | Feb 9 |
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) | Feb 22 | Dec 5 |
| Frost / freeze (32°F) | Jan 11 | Dec 21 |
| Hard freeze (28°F) | Dec 31 | Dec 29 |
Planting calendar for San Rafael
Transplant Jan 18 – Feb 1
Transplant Jan 25 – Feb 8
Transplant Jan 25 – Feb 8
Transplant Jan 18 – Feb 1
Sow or transplant Jan 18 – Feb 1
Sow or transplant Jan 18 – Feb 1
Sow or transplant Jan 25 – Feb 8
Sow or transplant Dec 14 – Dec 28
Fall sowing Oct 26 – Nov 23
Fall sowing Oct 26 – Nov 16
Fall sowing Oct 12 – Oct 26
Sow or transplant Dec 14 – Dec 28
Fall sowing Oct 12 – Nov 9
Transplant Dec 28 – Jan 11
Fall sowing Sep 28 – Oct 12
Transplant Dec 21 – Jan 4
Fall sowing Sep 28 – Oct 12
Fall sowing Sep 28 – Oct 12
Fall sowing Nov 9 – Nov 30
Fall sowing Oct 12 – Oct 26
Plant Dec 14 – Dec 28
Based on the average last frost (Jan 11) and first frost (Dec 21). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.