San Francisco, California frost dates
Frost is uncommon in San Francisco. NOAA's 1991–2020 normals give a 50% chance of a 32°F freeze after December 29 and before December 26. In practice that means a freeze in roughly half of winters or fewer, usually on just a night or two, so dates are a poor guide here. Gardeners here plan around heat and the cool season, not frost.
Frost risk by date
| Chance of frost | Spring: frost after | Fall: frost before |
|---|---|---|
| 90% | December 11 | January 13 |
| 70% | December 23 | January 1 |
| 50% | December 29 | December 26 |
| 30% | January 3 | December 21 |
| 10% | January 13 | December 11 |
Read the spring column like this: there is a 10% chance of a 32°F freeze after January 13. These are NOAA probabilities for the San Francisco International Airport weather station (USW00023234, elevation 2 m), 1991–2020.
Nearby cities
| City | Last frost (50%) | First frost (50%) | Distance |
|---|---|---|---|
| San Jose, CA | Jan 12 | Dec 22 | ~48 km |
| Sacramento, CA | Feb 22 | Nov 24 | ~137 km |
| Fresno, CA | Jan 14 | Dec 14 | ~251 km |
| Reno, NV | Apr 20 | Oct 23 | ~308 km |
| Bakersfield, CA | Jan 17 | Dec 15 | ~379 km |
| Medford, OR | Apr 8 | Oct 29 | ~530 km |