Frost dates in San Francisco, California

NOAA 1991–2020 normals for a 32 °F freeze. Low spots and the edge of town run colder than downtown.

Short answer

Frost is too rare in San Francisco to put a date on: at NOAA's San Francisco Dwtn station, 1 mile from the middle of San Francisco, it hit 32 °F in fewer than 1 year in 10. 3 nearby stations do, listed below. San Francisco is in USDA planting zone 10b.

Weather stations around San Francisco

The first row is the date most people in San Francisco go by. The others show how far the dates move across the area.

Station	Last spring frost	First fall frost	Frost-free
San Francisco Dwtn 1 mi away, 150 ft	Frost too rare to date (32 °F in under 1 year in 10)
San Francisco Oceanside 6 mi away, 8 ft	December 30 1 in 10 after March 13	December 25 1 in 10 by November 26	360 days
Oakland Museum 9 mi away, 30 ft	Frost too rare to date (32 °F in under 1 year in 10)
Richmond 10 mi away, 20 ft	January 4 1 in 10 after January 26	January 2 1 in 10 by December 11	363 days
Berkeley 11 mi away, 310 ft	January 3 1 in 10 after February 14	January 1 1 in 10 by December 10	363 days

Distances are from the middle of San Francisco as the Census Bureau maps it. The average date is NOAA's 50% date: half of years have a later last frost, or an earlier first one. Plan by the 1-in-10 date if a freeze would cost you plants. The planting zone is the USDA 2023 zone for ZIP code 94102, at the middle of the city.

Your exact ZIP code

San Francisco covers a lot of ground. For the station nearest your own street, and its planting zone, type your ZIP code.

How these dates work

Frost dates come from NOAA's 1991 to 2020 Climate Normals, which work out from each weather station's daily lows how likely the last spring freeze and the first fall freeze (32 °F) are by each date. We use the station nearest the middle of your ZIP code and show its height and distance, since a station on a hill or by a lake can differ from your yard.

The average date is the 50% date: half of years have a freeze after the spring date or before the fall one. The 1-in-10 dates are NOAA's 10% dates, the ones to plan by if a late freeze would cost you plants. Within one yard, cold air pools in low spots while walls and paving hold heat, so some corners freeze before others.

More frost dates

All of California, station by station.

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