Frost dates in Sunnyvale, California

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

Short answer

The average last spring frost in Sunnyvale is January 6, and the average first fall frost is December 23, from NOAA's Moffett Federal Airfield station, 2 miles from the middle of Sunnyvale. 1 year in 10 the last frost comes after February 4, and the first one by December 3. That leaves about 351 frost-free days. Sunnyvale is in USDA planting zone 10a.

Weather stations around Sunnyvale

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

Station	Last spring frost	First fall frost	Frost-free
Moffett Federal Airfield 2 mi away, 39 ft	January 6 1 in 10 after February 4	December 23 1 in 10 by December 3	351 days
San Jose 6 mi away, 51 ft	January 12 1 in 10 after February 14	December 22 1 in 10 by December 1	344 days
San Jose 7 mi away, 67 ft	January 2 1 in 10 after January 23	December 25 1 in 10 by December 4	357 days
Palo Alto 7 mi away, 25 ft	February 1 1 in 10 after March 4	December 7 1 in 10 by November 20	309 days
Newark 9 mi away, 10 ft	January 1 1 in 10 after January 22	December 27 1 in 10 by December 9	360 days

Distances are from the middle of Sunnyvale 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 94085, at the middle of the city.

Your exact ZIP code

Sunnyvale 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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