San Luis Obispo, CA 93443 Frost Dates
Frost dates for San Luis Obispo, CA, ZIP 93443
The last spring frost here typically falls around 01/16, about 141 days from today. The first fall frost typically arrives around 12/25, about 349 frost-free days later.
San Luis Obispo sits in USDA Zone 10a (30 to 35°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
Zone 10a around San Luis Obispo has about 17 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 01/16 isn't a guarantee
01/16 is the middle of 30 years of NOAA records, not a promise. Plant by 02/26 and you're betting against frost in roughly 9 years out of 10. 12/11 is the safer bet, historically only a 1-in-10 chance of frost that late.
How San Luis Obispo compares
About 349 days separate San Luis Obispo's last and first frost, putting it 2,340 of 40,283 ZIP codes nationally. Within CA, it ranks 1,046 of 2,555.
Learn more
local microclimates explains what one yard in San Luis Obispo can differ from the 93443 normal, and zone vs. frost date explains why Zone 10a and San Luis Obispo's frost date answer different questions.