Last spring frost
Apr 18
Frost Dates for Herriman, UT
First fall frost
Oct 22
Growing season
185 days
Hardiness zone
7a
In an average year around Herriman, UT, the last spring frost (32°F) is about Apr 18 and the first fall frost is about Oct 22, giving roughly a 185-day growing season. To be safe most years, wait until Mar 31 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 22 | May 2 | Apr 17 |
| Freeze (32°F) | May 6 | Apr 18 | Mar 31 |
| Hard (28°F) | Apr 17 | Mar 31 | Mar 7 |
| Severe (24°F) | Apr 2 | Mar 8 | Feb 19 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 22 | May 14 | May 9 | May 5 | May 2 | Apr 30 | Apr 26 | Apr 22 | Apr 17 |
| 32°F | May 6 | Apr 30 | Apr 25 | Apr 22 | Apr 18 | Apr 14 | Apr 10 | Apr 5 | Mar 31 |
| 28°F | Apr 17 | Apr 12 | Apr 7 | Apr 3 | Mar 31 | Mar 28 | Mar 21 | Mar 14 | Mar 7 |
| 24°F | Apr 2 | Mar 27 | Mar 19 | Mar 12 | Mar 8 | Mar 4 | Mar 1 | Feb 26 | Feb 19 |
| 20°F | Mar 12 | Mar 5 | Mar 1 | Feb 26 | Feb 22 | Feb 18 | Feb 14 | Feb 9 | Feb 3 |
| 16°F | Mar 1 | Feb 24 | Feb 19 | Feb 14 | Feb 10 | Feb 6 | Feb 1 | Jan 24 | Jan 11 |
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 27 | Oct 10 | Oct 23 |
| Freeze (32°F) | Oct 7 | Oct 22 | Nov 5 |
| Hard (28°F) | Oct 18 | Nov 2 | Nov 18 |
| Severe (24°F) | Oct 26 | Nov 13 | Dec 1 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 27 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 23 |
| 32°F | Oct 7 | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 24 | Oct 27 | Nov 1 | Nov 5 |
| 28°F | Oct 18 | Oct 22 | Oct 26 | Oct 29 | Nov 2 | Nov 5 | Nov 9 | Nov 13 | Nov 18 |
| 24°F | Oct 26 | Nov 1 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 20 | Nov 25 | Dec 1 |
| 20°F | Nov 6 | Nov 12 | Nov 16 | Nov 20 | Nov 24 | Nov 27 | Dec 1 | Dec 5 | Dec 12 |
| 16°F | Nov 14 | Nov 20 | Nov 26 | Nov 30 | Dec 4 | Dec 8 | Dec 14 | Dec 20 | Dec 29 |
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: Draper-Point Of Mtn, Ut, about 10.5 miles away@if(!empty($station['elevation_ft'])), at 4,506 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 Herriman, UT?
On average, the last spring frost (32°F) around Herriman, UT is about Apr 18. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 31.
When is the first frost in the fall?
The first fall frost around Herriman, UT typically arrives about Oct 22. 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 18 on average, or Mar 31 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 185 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 84096 Planting calendar → Utah frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026