Frost Dates for San Marcos, CA
In San Marcos, CA, the average last spring frost is around Jan 2 and the average first fall frost around Dec 30, for a growing season of about 365 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 Escondido #2, CA weather station, 5 miles away, elevation 600 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 8 |
| 20% | Jan 25 | Dec 15 |
| 30% | Jan 14 | Dec 23 |
| 40% | Jan 7 | Dec 27 |
| 50% | Jan 2 | Dec 30 |
| 60% | Dec 31 | Jan 1 |
| 70% | Dec 28 | Jan 7 |
| 80% | Dec 22 | Jan 14 |
| 90% | Dec 14 | Jan 29 |
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) | Jan 31 | Dec 18 |
| Frost / freeze (32°F) | Jan 2 | Dec 30 |
| Hard freeze (28°F) | — | — |
Planting calendar for San Marcos
Transplant Jan 9 – Jan 23
Transplant Jan 16 – Jan 30
Transplant Jan 16 – Jan 30
Transplant Jan 9 – Jan 23
Sow or transplant Jan 9 – Jan 23
Sow or transplant Jan 9 – Jan 23
Sow or transplant Jan 16 – Jan 30
Sow or transplant Dec 5 – Dec 19
Fall sowing Nov 4 – Dec 2
Fall sowing Nov 4 – Nov 25
Fall sowing Oct 21 – Nov 4
Sow or transplant Dec 5 – Dec 19
Fall sowing Oct 21 – Nov 18
Transplant Dec 19 – Jan 2
Fall sowing Oct 7 – Oct 21
Transplant Dec 12 – Dec 26
Fall sowing Oct 7 – Oct 21
Fall sowing Oct 7 – Oct 21
Fall sowing Nov 18 – Dec 9
Fall sowing Oct 21 – Nov 4
Plant Dec 5 – Dec 19
Based on the average last frost (Jan 2) and first frost (Dec 30). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.