Frost dates for Iron Mtn, 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
January 3
typical year
Safe to plant
February 11
frost is over in 9 of 10 years
First fall frost
December 31
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 6 – 20 | – |
| Spinach | – | Nov 22 – Dec 13 | Nov 5 – 19 |
| Lettuce | – | Dec 6 – 27 | Nov 5 – 19 |
| Radishes | – | Dec 6 – Jan 17 | Nov 19 – Dec 3 |
| Onions | – | Dec 6 – 20 | – |
| Potatoes | – | Dec 13 – 27 | – |
| Carrots | – | Dec 13 – Jan 3 | Oct 8 – 22 |
| Beets | – | Dec 6 – 20 | Oct 22 – Nov 5 |
| Kale | Oct 25 – Nov 8 | Dec 6 – 20 | Oct 22 – Nov 5 |
| Broccoli | Oct 25 – Nov 8 | Dec 20 – Jan 3 | Oct 22 – Nov 5 |
| Cabbage | Oct 11 – 25 | Dec 6 – 20 | Oct 22 – Nov 5 |
| Garlic | – | – | Nov 19 – Dec 10 |
| Warm-season crops | |||
| Tomatoes | Dec 17 – 31 | Feb 11 – 25 | – |
| Peppers | Dec 10 – 24 | Feb 18 – Mar 4 | – |
| Cucumbers | – | Feb 11 – Mar 4 | – |
| Zucchini | – | Feb 11 – Mar 11 | – |
| Pumpkins | – | Feb 11 – Mar 4 | – |
| Green beans | – | Feb 11 – Oct 22 | – |
| Sweet corn | – | Feb 11 – Mar 11 | – |
| Basil | Jan 7 – 21 | Feb 18 – 25 | – |
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 | February 11 | January 3 | December 12 |
| Fall frost before | December 6 | December 31 | January 30 |
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.
Where these dates come from
NOAA weather station IRON MTN, CA US (USC00044297), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 8 miles:
92280
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.