Frost dates for Alton, UT
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 1
typical year
Safe to plant
June 15
frost is over in 9 of 10 years
First fall frost
September 30
typical year
Growing season
120 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 4 – 18 | – |
| Spinach | – | Apr 20 – May 11 | Aug 5 – 19 |
| Lettuce | – | May 4 – 25 | Aug 5 – 19 |
| Radishes | – | May 4 – Jun 15 | Aug 19 – Sep 2 |
| Onions | – | May 4 – 18 | – |
| Potatoes | – | May 11 – 25 | – |
| Carrots | – | May 11 – Jun 1 | Jul 8 – 22 |
| Beets | – | May 4 – 18 | Jul 22 – Aug 5 |
| Kale | Mar 23 – Apr 6 | May 4 – 18 | Jul 22 – Aug 5 |
| Broccoli | Mar 23 – Apr 6 | May 18 – Jun 1 | Jul 22 – Aug 5 |
| Cabbage | Mar 9 – 23 | May 4 – 18 | Jul 22 – Aug 5 |
| Garlic | – | – | Aug 19 – Sep 9 |
| Warm-season crops | |||
| Tomatoes | Apr 20 – May 4 | Jun 15 – 29 | – |
| Peppers | Apr 13 – 27 | Jun 22 – Jul 6 | – |
| Cucumbers | – | Jun 15 – Jul 6 | – |
| Zucchini | – | Jun 15 – Jul 13 | – |
| Pumpkins | – | Jun 15 – Jul 6 | – |
| Green beans | – | Jun 15 – Jul 22 | – |
| Sweet corn | – | Jun 15 – Jul 13 | – |
| Basil | May 11 – 25 | Jun 22 – 29 | – |
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 15 | June 1 | May 16 |
| Fall frost before | September 16 | September 30 | October 12 |
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 17 (June 4 in a late year), and the first one in fall around October 11.
Towns that use these dates
This is the nearest NOAA station with frost records for 1 town.
Alton
Where these dates come from
NOAA weather station ALTON, UT US (USC00420086), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 3 miles:
84710
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.