Frost dates for San Mateo, CA
When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.
Last spring frost
December 29
typical year
Safe to plant
January 13
frost is over in 9 of 10 years
First fall frost
December 26
typical year
Growing season
365 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Dec 1 – 15 | – |
| Spinach | – | Nov 17 – Dec 8 | Oct 31 – Nov 14 |
| Lettuce | – | Dec 1 – 22 | Oct 31 – Nov 14 |
| Radishes | – | Dec 1 – Jan 12 | Nov 14 – 28 |
| Onions | – | Dec 1 – 15 | – |
| Potatoes | – | Dec 8 – 22 | – |
| Carrots | – | Dec 8 – 29 | Oct 3 – 17 |
| Beets | – | Dec 1 – 15 | Oct 17 – 31 |
| Kale | Oct 20 – Nov 3 | Dec 1 – 15 | Oct 17 – 31 |
| Broccoli | Oct 20 – Nov 3 | Dec 15 – 29 | Oct 17 – 31 |
| Cabbage | Oct 6 – 20 | Dec 1 – 15 | Oct 17 – 31 |
| Garlic | – | – | Nov 14 – Dec 5 |
| Warm-season crops | |||
| Tomatoes | Nov 18 – Dec 2 | Jan 13 – 27 | – |
| Peppers | Nov 11 – 25 | Jan 20 – Feb 3 | – |
| Cucumbers | – | Jan 13 – Feb 3 | – |
| Zucchini | – | Jan 13 – Feb 10 | – |
| Pumpkins | – | Jan 13 – Feb 3 | – |
| Green beans | – | Jan 13 – Oct 17 | – |
| Sweet corn | – | Jan 13 – Feb 10 | – |
| Basil | Dec 9 – 23 | Jan 20 – 27 | – |
Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.
The year at a glance
Start indoors Plant outside Fall planting
The chance of frost, by date
| 1 year in 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | January 13 | December 29 | December 11 |
| Fall frost before | December 11 | December 26 | January 13 |
Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.
Hard freeze (28°F)
A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around n/a (n/a in a late year), and the first one in fall around n/a.
Towns that use these dates
This is the nearest NOAA station with frost records for 6 towns.
San Mateo, South San Francisco, Burlingame, Millbrae, Hillsborough, Brisbane
Where these dates come from
NOAA weather station SAN FRANCISCO INTL AP, CA US (USW00023234), 1991–2020 climate normals. It's the nearest station for 7 zip codes, all within 6 miles:
94005, 94010, 94030, 94080, 94128, 94401, 94402
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.