Last frost date in San Mateo, California

December 29

Average last frost in spring. In an early year (1 in 10) it's over by December 11; in a late year (1 in 10) it comes after January 13.

December 26

Average first frost in fall. 1 year in 10 it comes by December 11.

A 32°F night happens here about 1 years in 10; in those years these are the usual dates.

Source: NOAA U.S. Climate Normals 1991–2020, station San Francisco International AP (USW00023234), 5.1 miles from San Mateo, elevation 8 ft. NOAA National Centers for Environmental Information. These are long-term averages, not a forecast.

This station is also the nearest one for Burlingame, Hillsborough, Millbrae and South San Francisco, so their frost dates are the same as San Mateo's.

What to plant now

Frost dates for San Mateo, California
Early yearAverageLate year
Last frost in springDec 11Dec 29Jan 13
First frost in fallDec 11Dec 26Jan 13

Frost-free days in an average year: 365

Light frost, frost and hard freeze in San Mateo
Chance in a yearAverage last in springAverage first in fall
Light frost (36°F)7 years in 10Jan 8Dec 24
Frost (32°F)1 years in 10Dec 29Dec 26
Hard freeze (28°F)Under 1 year in 20——

Nights at 32°F or colder in an average year: 0.2

What to plant now in San Mateo

Planting dates: USDA Home and Garden Bulletin No. 9 (1967), “Suburban and Farm Vegetable Gardens,” tables 4 and 5. How we match the table.

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