Frost Dates for San Luis Obispo, CA
In San Luis Obispo, CA, the average last spring frost is around Jan 31 and the average first fall frost around Dec 11, for a growing season of about 319 days. For frost-tender plants, wait until Mar 7, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the San Luis Obispo Airport, CA weather station, 3 miles away, elevation 200 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% | Mar 7 | Nov 20 |
| 20% | Feb 25 | Nov 28 |
| 30% | Feb 17 | Dec 2 |
| 40% | Feb 7 | Dec 6 |
| 50% | Jan 31 | Dec 11 |
| 60% | Jan 23 | Dec 15 |
| 70% | Jan 13 | Dec 23 |
| 80% | Jan 3 | Jan 1 |
| 90% | Dec 23 | Jan 13 |
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) | Mar 17 | Nov 24 |
| Frost / freeze (32°F) | Jan 31 | Dec 11 |
| Hard freeze (28°F) | Jan 3 | Dec 28 |
Planting calendar for San Luis Obispo
Transplant Feb 7 – Feb 21
Transplant Feb 14 – Feb 28
Transplant Feb 14 – Feb 28
Transplant Feb 7 – Feb 21
Sow or transplant Feb 7 – Feb 21
Sow or transplant Feb 7 – Feb 21
Sow or transplant Feb 14 – Feb 28
Sow or transplant Jan 3 – Jan 17
Fall sowing Oct 16 – Nov 13
Fall sowing Oct 16 – Nov 6
Fall sowing Oct 2 – Oct 16
Sow or transplant Jan 3 – Jan 17
Fall sowing Oct 2 – Oct 30
Transplant Jan 17 – Jan 31
Fall sowing Sep 18 – Oct 2
Transplant Jan 10 – Jan 24
Fall sowing Sep 18 – Oct 2
Fall sowing Sep 18 – Oct 2
Fall sowing Oct 30 – Nov 20
Fall sowing Oct 2 – Oct 16
Plant Jan 3 – Jan 17
Based on the average last frost (Jan 31) and first frost (Dec 11). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.