Frost dates for San Ramon, 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
March 8
typical year
Safe to plant
April 15
frost is over in 9 of 10 years
First fall frost
December 22
typical year
Growing season
282 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 | – | Feb 8 – 22 | – |
| Spinach | – | Jan 25 – Feb 15 | Oct 27 – Nov 10 |
| Lettuce | – | Feb 8 – Mar 1 | Oct 27 – Nov 10 |
| Radishes | – | Feb 8 – Mar 22 | Nov 10 – 24 |
| Onions | – | Feb 8 – 22 | – |
| Potatoes | – | Feb 15 – Mar 1 | – |
| Carrots | – | Feb 15 – Mar 8 | Sep 29 – Oct 13 |
| Beets | – | Feb 8 – 22 | Oct 13 – 27 |
| Kale | Dec 28 – Jan 11 | Feb 8 – 22 | Oct 13 – 27 |
| Broccoli | Dec 28 – Jan 11 | Feb 22 – Mar 8 | Oct 13 – 27 |
| Cabbage | Dec 14 – 28 | Feb 8 – 22 | Oct 13 – 27 |
| Garlic | – | – | Nov 10 – Dec 1 |
| Warm-season crops | |||
| Tomatoes | Feb 18 – Mar 4 | Apr 15 – 29 | – |
| Peppers | Feb 11 – 25 | Apr 22 – May 6 | – |
| Cucumbers | – | Apr 15 – May 6 | – |
| Zucchini | – | Apr 15 – May 13 | – |
| Pumpkins | – | Apr 15 – May 6 | – |
| Green beans | – | Apr 15 – Oct 13 | – |
| Sweet corn | – | Apr 15 – May 13 | – |
| Basil | Mar 11 – 25 | Apr 22 – 29 | – |
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 | April 15 | March 8 | January 12 |
| Fall frost before | November 23 | December 22 | February 11 |
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 February 8 (March 23 in a late year), and the first one in fall around January 16.
Towns that use these dates
This is the nearest NOAA station with frost records for 3 towns.
San Ramon, Danville, Clayton
Where these dates come from
NOAA weather station MT DIABLO JUNCTION, CA US (USC00045915), 1991–2020 climate normals. It's the nearest station for 10 zip codes, all within 8 miles:
94506, 94507, 94517, 94526, 94528, 94583, 94588, 94595, 94596, 94598
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.