Last spring frost
Jun 1
Frost Dates for Vernon, UT
First fall frost
Sep 20
Growing season
110 days
Hardiness zone
6b
In an average year around Vernon, UT, the last spring frost (32°F) is about Jun 1 and the first fall frost is about Sep 20, giving roughly a 110-day growing season. To be safe most years, wait until May 18 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Jun 28 | Jun 13 | May 31 |
| Freeze (32°F) | Jun 19 | Jun 1 | May 18 |
| Hard (28°F) | Jun 8 | May 19 | May 3 |
| Severe (24°F) | May 28 | May 5 | Apr 18 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 28 | Jun 23 | Jun 20 | Jun 17 | Jun 13 | Jun 10 | Jun 7 | Jun 3 | May 31 |
| 32°F | Jun 19 | Jun 13 | Jun 8 | Jun 5 | Jun 1 | May 30 | May 27 | May 22 | May 18 |
| 28°F | Jun 8 | Jun 1 | May 28 | May 23 | May 19 | May 16 | May 13 | May 9 | May 3 |
| 24°F | May 28 | May 18 | May 14 | May 9 | May 5 | May 2 | Apr 28 | Apr 24 | Apr 18 |
| 20°F | May 11 | May 4 | Apr 29 | Apr 24 | Apr 20 | Apr 17 | Apr 12 | Apr 7 | Apr 2 |
| 16°F | Apr 21 | Apr 14 | Apr 9 | Apr 5 | Apr 1 | Mar 29 | Mar 24 | Mar 17 | Mar 10 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Aug 26 | Sep 9 | Sep 25 |
| Freeze (32°F) | Sep 4 | Sep 20 | Oct 3 |
| Hard (28°F) | Sep 15 | Sep 29 | Oct 13 |
| Severe (24°F) | Sep 23 | Oct 9 | Oct 24 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 26 | Sep 1 | Sep 4 | Sep 7 | Sep 9 | Sep 13 | Sep 16 | Sep 20 | Sep 25 |
| 32°F | Sep 4 | Sep 9 | Sep 13 | Sep 17 | Sep 20 | Sep 22 | Sep 26 | Sep 29 | Oct 3 |
| 28°F | Sep 15 | Sep 20 | Sep 24 | Sep 27 | Sep 29 | Oct 1 | Oct 5 | Oct 8 | Oct 13 |
| 24°F | Sep 23 | Sep 29 | Oct 2 | Oct 6 | Oct 9 | Oct 13 | Oct 16 | Oct 20 | Oct 24 |
| 20°F | Oct 3 | Oct 9 | Oct 15 | Oct 19 | Oct 23 | Oct 25 | Oct 28 | Nov 1 | Nov 6 |
| 16°F | Oct 16 | Oct 23 | Oct 27 | Oct 31 | Nov 2 | Nov 6 | Nov 9 | Nov 13 | Nov 18 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Vernon, Ut, about 4.4 miles away@if(!empty($station['elevation_ft'])), at 5,471 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Vernon, UT?
On average, the last spring frost (32°F) around Vernon, UT is about Jun 1. In cooler years it can run later, so for a safer bet many gardeners wait until May 18.
When is the first frost in the fall?
The first fall frost around Vernon, UT typically arrives about Sep 20. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Jun 1 on average, or May 18 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 110 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 84080 Planting calendar → Utah frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026