Frost dates for Alta, WY
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 14
typical year
Safe to plant
July 4
frost is over in 9 of 10 years
First fall frost
September 11
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 17 – 31 | – |
| Spinach | – | May 3 – 24 | Jul 17 – 31 |
| Lettuce | – | May 17 – Jun 7 | Jul 17 – 31 |
| Radishes | – | May 17 – Jun 28 | Jul 31 – Aug 14 |
| Onions | – | May 17 – 31 | – |
| Potatoes | Season usually too short. Try a quick variety or row covers. | ||
| Carrots | – | May 24 – Jun 14 | Jun 19 – Jul 3 |
| Beets | – | May 17 – 31 | Jul 3 – 17 |
| Kale | Apr 5 – 19 | May 17 – 31 | Jul 3 – 17 |
| Broccoli | Apr 5 – 19 | May 31 – Jun 14 | Jul 3 – 17 |
| Cabbage | Mar 22 – Apr 5 | May 17 – 31 | Jul 3 – 17 |
| Garlic | – | – | Jul 31 – Aug 21 |
| 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 | – | Jul 4 – 25 | – |
| Zucchini | – | Jul 4 – Aug 1 | – |
| Pumpkins | Season usually too short. Try a quick variety or row covers. | ||
| Green beans | Season usually too short. Try a quick variety or row covers. | ||
| Sweet corn | Season usually too short. Try a quick variety or row covers. | ||
| Basil | May 30 – Jun 13 | Jul 11 – 18 | – |
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 | July 4 | June 14 | May 23 |
| Fall frost before | August 28 | September 11 | September 26 |
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 24 (June 15 in a late year), and the first one in fall around September 23.
Where these dates come from
NOAA weather station ALTA 1 NNW, WY US (USC00480140), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 8 miles:
83414
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.