Frost Dates for Sunnyvale, CA
In Sunnyvale, CA, the average last spring frost is around Jan 6 and the average first fall frost around Dec 23, for a growing season of about 353 days. For frost-tender plants, wait until Feb 4, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Moffett Federal Airfield, CA weather station, 2 miles away, elevation 39 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 4 | Dec 3 |
| 20% | Jan 26 | Dec 9 |
| 30% | Jan 18 | Dec 15 |
| 40% | Jan 11 | Dec 19 |
| 50% | Jan 6 | Dec 23 |
| 60% | Jan 1 | Dec 28 |
| 70% | Dec 29 | Jan 1 |
| 80% | Dec 24 | Jan 6 |
| 90% | Dec 16 | Jan 16 |
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 6 | Dec 6 |
| Frost / freeze (32°F) | Jan 6 | Dec 23 |
| Hard freeze (28°F) | Jan 1 | Dec 31 |
Planting calendar for Sunnyvale
Transplant Jan 13 – Jan 27
Transplant Jan 20 – Feb 3
Transplant Jan 20 – Feb 3
Transplant Jan 13 – Jan 27
Sow or transplant Jan 13 – Jan 27
Sow or transplant Jan 13 – Jan 27
Sow or transplant Jan 20 – Feb 3
Sow or transplant Dec 9 – Dec 23
Fall sowing Oct 28 – Nov 25
Fall sowing Oct 28 – Nov 18
Fall sowing Oct 14 – Oct 28
Sow or transplant Dec 9 – Dec 23
Fall sowing Oct 14 – Nov 11
Transplant Dec 23 – Jan 6
Fall sowing Sep 30 – Oct 14
Transplant Dec 16 – Dec 30
Fall sowing Sep 30 – Oct 14
Fall sowing Sep 30 – Oct 14
Fall sowing Nov 11 – Dec 2
Fall sowing Oct 14 – Oct 28
Plant Dec 9 – Dec 23
Based on the average last frost (Jan 6) and first frost (Dec 23). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.