Frost dates for San Francisco Intl Airport, CA
At this NOAA station the last spring frost (32°F) usually comes by December 29 and the first fall frost around December 26, giving a growing season of about 365 days.
December 29average last spring frost
December 26average first fall frost
Frost odds
| 1 year in 10 the last spring frost is later than | January 13 |
| Half of years the last spring frost is later than | December 29 |
| 9 years in 10 the last spring frost is later than | December 11 |
| 1 year in 10 the first fall frost is earlier than | December 11 |
| Half of years the first fall frost is earlier than | December 26 |
| 9 years in 10 the first fall frost is earlier than | January 13 |
A light frost (36°F, which can still nip tender plants) usually ends by January 8 and returns around December 24.
Station USW00023234, elevation 2 m. Based on 26 years of 1991 to 2020 records. A garden higher up, in a hollow or far from this station can freeze later in spring.
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Sources
- U.S. Annual/Seasonal Climate Normals, 1991 to 2020 (freeze probability dates by station), NOAA National Centers for Environmental Information, checked 1 November 2026
- Annual/Seasonal Normals 1991 to 2020 documentation, NOAA National Centers for Environmental Information, checked 1 November 2026
- 2024 Gazetteer Files, ZIP Code Tabulation Areas, US Census Bureau, checked 1 November 2026