Last spring frost
May 30
Frost Dates for Henefer, UT
First fall frost
Sep 18
Growing season
112 days
Hardiness zone
6a
In an average year around Henefer, UT, the last spring frost (32°F) is about May 30 and the first fall frost is about Sep 18, giving roughly a 112-day growing season. To be safe most years, wait until May 11 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 30 | Jun 15 | May 31 |
| Freeze (32°F) | Jun 16 | May 30 | May 11 |
| Hard (28°F) | May 31 | May 10 | Apr 25 |
| Severe (24°F) | May 13 | Apr 26 | Apr 8 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 30 | Jun 24 | Jun 21 | Jun 18 | Jun 15 | Jun 12 | Jun 8 | Jun 4 | May 31 |
| 32°F | Jun 16 | Jun 10 | Jun 5 | Jun 1 | May 30 | May 26 | May 22 | May 17 | May 11 |
| 28°F | May 31 | May 24 | May 18 | May 14 | May 10 | May 7 | May 4 | Apr 30 | Apr 25 |
| 24°F | May 13 | May 7 | May 3 | Apr 30 | Apr 26 | Apr 22 | Apr 18 | Apr 13 | Apr 8 |
| 20°F | Apr 27 | Apr 20 | Apr 16 | Apr 11 | Apr 8 | Apr 4 | Apr 1 | Mar 27 | Mar 17 |
| 16°F | Apr 12 | Apr 5 | Mar 31 | Mar 26 | Mar 21 | Mar 16 | Mar 12 | Mar 9 | Mar 3 |
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 23 | Sep 8 | Sep 22 |
| Freeze (32°F) | Sep 4 | Sep 18 | Oct 1 |
| Hard (28°F) | Sep 17 | Oct 1 | Oct 14 |
| Severe (24°F) | Sep 29 | Oct 11 | Oct 26 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 23 | Aug 31 | Sep 2 | Sep 6 | Sep 8 | Sep 11 | Sep 14 | Sep 18 | Sep 22 |
| 32°F | Sep 4 | Sep 9 | Sep 13 | Sep 15 | Sep 18 | Sep 21 | Sep 24 | Sep 27 | Oct 1 |
| 28°F | Sep 17 | Sep 21 | Sep 25 | Sep 27 | Oct 1 | Oct 3 | Oct 5 | Oct 9 | Oct 14 |
| 24°F | Sep 29 | Oct 2 | Oct 5 | Oct 8 | Oct 11 | Oct 15 | Oct 17 | Oct 22 | Oct 26 |
| 20°F | Oct 10 | Oct 15 | Oct 19 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 2 | Nov 6 |
| 16°F | Oct 20 | Oct 25 | Oct 28 | Oct 31 | Nov 3 | Nov 6 | Nov 10 | 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: Echo Dam, Ut, about 3.2 miles away@if(!empty($station['elevation_ft'])), at 5,470 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 Henefer, UT?
On average, the last spring frost (32°F) around Henefer, UT is about May 30. In cooler years it can run later, so for a safer bet many gardeners wait until May 11.
When is the first frost in the fall?
The first fall frost around Henefer, UT typically arrives about Sep 18. 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 May 30 on average, or May 11 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 112 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 84033 Planting calendar → Utah frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026