Frost dates for Powell, 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
May 31
typical year
Safe to plant
June 26
frost is over in 9 of 10 years
First fall frost
September 12
typical year
Growing season
102 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 3 – 17 | – |
| Spinach | – | Apr 19 – May 10 | Jul 18 – Aug 1 |
| Lettuce | – | May 3 – 24 | Jul 18 – Aug 1 |
| Radishes | – | May 3 – Jun 14 | Aug 1 – 15 |
| Onions | – | May 3 – 17 | – |
| Potatoes | Season usually too short. Try a quick variety or row covers. | ||
| Carrots | – | May 10 – 31 | Jun 20 – Jul 4 |
| Beets | – | May 3 – 17 | Jul 4 – 18 |
| Kale | Mar 22 – Apr 5 | May 3 – 17 | Jul 4 – 18 |
| Broccoli | Mar 22 – Apr 5 | May 17 – 31 | Jul 4 – 18 |
| Cabbage | Mar 8 – 22 | May 3 – 17 | Jul 4 – 18 |
| Garlic | – | – | Aug 1 – 22 |
| Warm-season crops | |||
| Tomatoes | May 1 – 15 | Jun 26 – Jul 10 | – |
| Peppers | Season usually too short. Try a quick variety or row covers. | ||
| Cucumbers | – | Jun 26 – Jul 17 | – |
| Zucchini | – | Jun 26 – Jul 24 | – |
| Pumpkins | Season usually too short. Try a quick variety or row covers. | ||
| Green beans | – | Jun 26 – Jul 4 | – |
| Sweet corn | Season usually too short. Try a quick variety or row covers. | ||
| Basil | May 22 – Jun 5 | Jul 3 – 10 | – |
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 26 | May 31 | May 14 |
| Fall frost before | August 28 | September 12 | October 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 May 9 (May 26 in a late year), and the first one in fall around September 30.
Where these dates come from
NOAA weather station POWELL, ID US (USC00107320), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 19 miles:
83539
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.