Frost dates for St. Helena, 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
February 3
typical year
Safe to plant
March 13
frost is over in 9 of 10 years
First fall frost
December 4
typical year
Growing season
306 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 | – | Jan 6 – 20 | – |
| Spinach | – | Dec 23 – Jan 13 | Oct 9 – 23 |
| Lettuce | – | Jan 6 – 27 | Oct 9 – 23 |
| Radishes | – | Jan 6 – Feb 17 | Oct 23 – Nov 6 |
| Onions | – | Jan 6 – 20 | – |
| Potatoes | – | Jan 13 – 27 | – |
| Carrots | – | Jan 13 – Feb 3 | Sep 11 – 25 |
| Beets | – | Jan 6 – 20 | Sep 25 – Oct 9 |
| Kale | Nov 25 – Dec 9 | Jan 6 – 20 | Sep 25 – Oct 9 |
| Broccoli | Nov 25 – Dec 9 | Jan 20 – Feb 3 | Sep 25 – Oct 9 |
| Cabbage | Nov 11 – 25 | Jan 6 – 20 | Sep 25 – Oct 9 |
| Garlic | – | – | Oct 23 – Nov 13 |
| Warm-season crops | |||
| Tomatoes | Jan 16 – 30 | Mar 13 – 27 | – |
| Peppers | Jan 9 – 23 | Mar 20 – Apr 3 | – |
| Cucumbers | – | Mar 13 – Apr 3 | – |
| Zucchini | – | Mar 13 – Apr 10 | – |
| Pumpkins | – | Mar 13 – Apr 3 | – |
| Green beans | – | Mar 13 – Sep 25 | – |
| Sweet corn | – | Mar 13 – Apr 10 | – |
| Basil | Feb 6 – 20 | Mar 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 | March 13 | February 3 | December 28 |
| Fall frost before | November 14 | December 4 | January 1 |
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 January 5 (February 9 in a late year), and the first one in fall around December 17.
Towns that use these dates
This is the nearest NOAA station with frost records for 1 town.
St. Helena
Where these dates come from
NOAA weather station SAINT HELENA, CA US (USC00047643), 1991–2020 climate normals. It's the nearest station for 4 zip codes, all within 6 miles:
94562, 94573, 95409, 95452
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.