Frost dates for Tetonia Exp Stn, ID
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
June 15
typical year
Safe to plant
June 29
frost is over in 9 of 10 years
First fall frost
September 7
typical year
Growing season
85 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 | – | May 18 – Jun 1 | – |
| Spinach | – | May 4 – 25 | Jul 13 – 27 |
| Lettuce | – | May 18 – Jun 8 | Jul 13 – 27 |
| Radishes | – | May 18 – Jun 29 | Jul 27 – Aug 10 |
| Onions | – | May 18 – Jun 1 | – |
| Potatoes | Season usually too short. Try a quick variety or row covers. | ||
| Carrots | – | May 25 – Jun 15 | Jun 15 – 29 |
| Beets | – | May 18 – Jun 1 | Jun 29 – Jul 13 |
| Kale | Apr 6 – 20 | May 18 – Jun 1 | Jun 29 – Jul 13 |
| Broccoli | Apr 6 – 20 | Jun 1 – 15 | Jun 29 – Jul 13 |
| Cabbage | Mar 23 – Apr 6 | May 18 – Jun 1 | Jun 29 – Jul 13 |
| Garlic | – | – | Jul 27 – Aug 17 |
| Warm-season crops | |||
| Tomatoes | Season usually too short. Try a quick variety or row covers. | ||
| Peppers | Season usually too short. Try a quick variety or row covers. | ||
| Cucumbers | – | Jun 29 – Jul 20 | – |
| Zucchini | – | Jun 29 – Jul 27 | – |
| Pumpkins | Season usually too short. Try a quick variety or row covers. | ||
| Green beans | – | Jun 29 | – |
| Sweet corn | Season usually too short. Try a quick variety or row covers. | ||
| Basil | May 25 – Jun 8 | Jul 6 – 13 | – |
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 | June 29 | June 15 | May 24 |
| Fall frost before | August 24 | September 7 | September 23 |
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 May 21 (June 14 in a late year), and the first one in fall around September 20.
Where these dates come from
NOAA weather station TETONIA EXP STN, ID US (USC00109065), 1991–2020 climate normals. It's the nearest station for 3 zip codes, all within 9 miles:
83424, 83436, 83452
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.