San Mateo, CA 94497 Frost Dates
When can you plant in San Mateo, CA?
The last spring frost here typically falls around 01/17, about 142 days from today. The first fall frost typically arrives around 12/12, about 333 frost-free days later.
The USDA Plant Hardiness Zone Map puts San Mateo in Zone 10a (30 to 35°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
About 15 weeks of growing season left in San Mateo before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
01/17 is the middle of 30 years of NOAA records, not a promise. Plant by 02/16 and you're betting against frost in roughly 9 years out of 10. 12/20 is the safer bet, historically only a 1-in-10 chance of frost that late.
How San Mateo compares
About 333 days separate San Mateo's last and first frost, putting it 2,816 of 40,283 ZIP codes nationally. Within CA, it ranks 1,281 of 2,555.
Learn more
the frost range covers how to read the range around San Mateo's dates instead of trusting one. local microclimates covers what one yard in San Mateo can differ from the 94497 normal.