San Luis Obispo, CA 93407 Frost Dates
Frost dates for San Luis Obispo, CA, ZIP 93407
Around 01/16 is the usual last spring frost, about 141 days away. The first fall frost typically arrives around 12/25, about 349 frost-free days later.
San Luis Obispo sits in USDA Zone 9b (25 to 30°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 9b 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.
How much risk comes with planting early here
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
At roughly 349 frost-free days, San Luis Obispo places 2,336 of 40,283 ZIP codes in this dataset. Within CA, it ranks 1,042 of 2,555.
Learn more
zone vs. frost date explains why Zone 9b and San Luis Obispo's frost date answer different questions, and the frost range explains how to read the range around San Luis Obispo's dates instead of trusting one.