Last spring frost
Apr 22
Frost Dates for Green River, UT
First fall frost
Oct 20
Growing season
179 days
Hardiness zone
6b
In an average year around Green River, UT, the last spring frost (32°F) is about Apr 22 and the first fall frost is about Oct 20, giving roughly a 179-day growing season. To be safe most years, wait until Apr 7 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) | May 20 | May 3 | Apr 20 |
| Freeze (32°F) | May 8 | Apr 22 | Apr 7 |
| Hard (28°F) | Apr 27 | Apr 8 | Mar 21 |
| Severe (24°F) | Apr 11 | Mar 23 | Mar 2 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 20 | May 13 | May 9 | May 5 | May 3 | Apr 30 | Apr 28 | Apr 25 | Apr 20 |
| 32°F | May 8 | May 3 | Apr 29 | Apr 26 | Apr 22 | Apr 20 | Apr 16 | Apr 12 | Apr 7 |
| 28°F | Apr 27 | Apr 21 | Apr 16 | Apr 11 | Apr 8 | Apr 5 | Apr 2 | Mar 29 | Mar 21 |
| 24°F | Apr 11 | Apr 5 | Apr 1 | Mar 28 | Mar 23 | Mar 19 | Mar 13 | Mar 9 | Mar 2 |
| 20°F | Mar 25 | Mar 15 | Mar 9 | Mar 5 | Mar 2 | Feb 28 | Feb 24 | Feb 18 | Feb 12 |
| 16°F | Mar 6 | Mar 1 | Feb 25 | Feb 19 | Feb 16 | Feb 12 | Feb 7 | Feb 2 | Jan 26 |
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) | Sep 28 | Oct 10 | Oct 22 |
| Freeze (32°F) | Oct 6 | Oct 20 | Nov 1 |
| Hard (28°F) | Oct 15 | Oct 30 | Nov 9 |
| Severe (24°F) | Oct 25 | Nov 7 | Nov 18 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 28 | Oct 2 | Oct 5 | Oct 7 | Oct 10 | Oct 13 | Oct 15 | Oct 18 | Oct 22 |
| 32°F | Oct 6 | Oct 10 | Oct 14 | Oct 17 | Oct 20 | Oct 22 | Oct 25 | Oct 28 | Nov 1 |
| 28°F | Oct 15 | Oct 20 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 6 | Nov 9 |
| 24°F | Oct 25 | Oct 30 | Nov 3 | Nov 5 | Nov 7 | Nov 9 | Nov 11 | Nov 14 | Nov 18 |
| 20°F | Nov 3 | Nov 7 | Nov 10 | Nov 13 | Nov 15 | Nov 18 | Nov 19 | Nov 22 | Nov 27 |
| 16°F | Nov 9 | Nov 14 | Nov 18 | Nov 21 | Nov 24 | Nov 26 | Nov 30 | Dec 4 | Dec 10 |
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: Moab Canyonland Ap, Ut, about 33.4 miles away@if(!empty($station['elevation_ft'])), at 4,561 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 Green River, UT?
On average, the last spring frost (32°F) around Green River, UT is about Apr 22. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 7.
When is the first frost in the fall?
The first fall frost around Green River, UT typically arrives about Oct 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 Apr 22 on average, or Apr 7 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 179 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 84525 Planting calendar → Utah frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026