Frost Dates for Porterville, CA
In Porterville, CA, the average last spring frost is around Jan 20 and the average first fall frost around Dec 13, for a growing season of about 330 days. For frost-tender plants, wait until Feb 22, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Porterville, CA weather station, under 1 mile away, elevation 393 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 22 | Nov 26 |
| 20% | Feb 6 | Dec 1 |
| 30% | Jan 31 | Dec 5 |
| 40% | Jan 26 | Dec 9 |
| 50% | Jan 20 | Dec 13 |
| 60% | Jan 14 | Dec 16 |
| 70% | Jan 7 | Dec 21 |
| 80% | Jan 1 | Dec 28 |
| 90% | Dec 25 | Jan 6 |
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 26 | Nov 28 |
| Frost / freeze (32°F) | Jan 20 | Dec 13 |
| Hard freeze (28°F) | Dec 31 | Dec 23 |
Planting calendar for Porterville
Transplant Jan 27 – Feb 10
Transplant Feb 3 – Feb 17
Transplant Feb 3 – Feb 17
Transplant Jan 27 – Feb 10
Sow or transplant Jan 27 – Feb 10
Sow or transplant Jan 27 – Feb 10
Sow or transplant Feb 3 – Feb 17
Sow or transplant Dec 23 – Jan 6
Fall sowing Oct 18 – Nov 15
Fall sowing Oct 18 – Nov 8
Fall sowing Oct 4 – Oct 18
Sow or transplant Dec 23 – Jan 6
Fall sowing Oct 4 – Nov 1
Transplant Jan 6 – Jan 20
Fall sowing Sep 20 – Oct 4
Transplant Dec 30 – Jan 13
Fall sowing Sep 20 – Oct 4
Fall sowing Sep 20 – Oct 4
Fall sowing Nov 1 – Nov 22
Fall sowing Oct 4 – Oct 18
Plant Dec 23 – Jan 6
Based on the average last frost (Jan 20) and first frost (Dec 13). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.