Last spring frost
May 12
Frost Dates for Millville, UT
First fall frost
Sep 28
Growing season
138 days
Hardiness zone
6a
In an average year around Millville, UT, the last spring frost (32°F) is about May 12 and the first fall frost is about Sep 28, giving roughly a 138-day growing season. To be safe most years, wait until Apr 30 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 16 | May 31 | May 14 |
| Freeze (32°F) | May 29 | May 12 | Apr 30 |
| Hard (28°F) | May 12 | Apr 28 | Apr 9 |
| Severe (24°F) | May 1 | Apr 8 | Mar 16 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 16 | Jun 11 | Jun 7 | Jun 3 | May 31 | May 28 | May 24 | May 20 | May 14 |
| 32°F | May 29 | May 22 | May 18 | May 15 | May 12 | May 9 | May 7 | May 3 | Apr 30 |
| 28°F | May 12 | May 8 | May 4 | May 1 | Apr 28 | Apr 25 | Apr 21 | Apr 16 | Apr 9 |
| 24°F | May 1 | Apr 24 | Apr 18 | Apr 12 | Apr 8 | Apr 3 | Mar 31 | Mar 25 | Mar 16 |
| 20°F | Apr 11 | Apr 3 | Mar 31 | Mar 25 | Mar 20 | Mar 16 | Mar 13 | Mar 9 | Mar 5 |
| 16°F | Mar 28 | Mar 20 | Mar 15 | Mar 12 | Mar 9 | Mar 6 | Mar 4 | Mar 2 | Feb 25 |
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 4 | Sep 18 | Oct 2 |
| Freeze (32°F) | Sep 14 | Sep 28 | Oct 12 |
| Hard (28°F) | Sep 26 | Oct 9 | Oct 24 |
| Severe (24°F) | Oct 6 | Oct 23 | Nov 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 4 | Sep 9 | Sep 12 | Sep 15 | Sep 18 | Sep 21 | Sep 24 | Sep 28 | Oct 2 |
| 32°F | Sep 14 | Sep 18 | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 4 | Oct 8 | Oct 12 |
| 28°F | Sep 26 | Sep 30 | Oct 4 | Oct 6 | Oct 9 | Oct 12 | Oct 15 | Oct 19 | Oct 24 |
| 24°F | Oct 6 | Oct 12 | Oct 16 | Oct 19 | Oct 23 | Oct 25 | Oct 29 | Nov 2 | Nov 7 |
| 20°F | Oct 17 | Oct 23 | Oct 27 | Oct 31 | Nov 3 | Nov 6 | Nov 10 | Nov 16 | Nov 21 |
| 16°F | Oct 27 | Nov 1 | Nov 8 | Nov 12 | Nov 16 | Nov 20 | Nov 23 | Nov 26 | Dec 1 |
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: Logan 5 Sw Exp Farm, Ut, about 3.8 miles away@if(!empty($station['elevation_ft'])), at 4,488 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 Millville, UT?
On average, the last spring frost (32°F) around Millville, UT is about May 12. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 30.
When is the first frost in the fall?
The first fall frost around Millville, UT typically arrives about Sep 28. 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 12 on average, or Apr 30 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 138 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 84326 Planting calendar → Utah frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026