Last spring frost
May 21
Frost Dates for Malta, UT
First fall frost
Oct 2
Growing season
132 days
Hardiness zone
6a
In an average year around Malta, UT, the last spring frost (32°F) is about May 21 and the first fall frost is about Oct 2, giving roughly a 132-day growing season. To be safe most years, wait until May 2 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 21 | Jun 4 | May 18 |
| Freeze (32°F) | Jun 11 | May 21 | May 2 |
| Hard (28°F) | May 25 | May 3 | Apr 16 |
| Severe (24°F) | May 10 | Apr 18 | Mar 28 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 21 | Jun 15 | Jun 11 | Jun 8 | Jun 4 | Jun 1 | May 30 | May 24 | May 18 |
| 32°F | Jun 11 | Jun 4 | May 31 | May 26 | May 21 | May 17 | May 12 | May 8 | May 2 |
| 28°F | May 25 | May 17 | May 12 | May 7 | May 3 | Apr 30 | Apr 27 | Apr 22 | Apr 16 |
| 24°F | May 10 | May 1 | Apr 25 | Apr 21 | Apr 18 | Apr 14 | Apr 9 | Apr 3 | Mar 28 |
| 20°F | Apr 21 | Apr 14 | Apr 8 | Apr 4 | Mar 31 | Mar 26 | Mar 19 | Mar 15 | Mar 9 |
| 16°F | Apr 8 | Mar 30 | Mar 21 | Mar 14 | Mar 10 | Mar 7 | Mar 3 | Feb 28 | Feb 20 |
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 8 | Sep 24 | Oct 7 |
| Freeze (32°F) | Sep 17 | Oct 2 | Oct 17 |
| Hard (28°F) | Sep 27 | Oct 12 | Oct 27 |
| Severe (24°F) | Oct 5 | Oct 23 | Nov 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 8 | Sep 13 | Sep 17 | Sep 20 | Sep 24 | Sep 26 | Sep 28 | Oct 1 | Oct 7 |
| 32°F | Sep 17 | Sep 23 | Sep 26 | Sep 29 | Oct 2 | Oct 5 | Oct 8 | Oct 12 | Oct 17 |
| 28°F | Sep 27 | Oct 1 | Oct 5 | Oct 8 | Oct 12 | Oct 15 | Oct 19 | Oct 23 | Oct 27 |
| 24°F | Oct 5 | Oct 11 | Oct 16 | Oct 20 | Oct 23 | Oct 27 | Oct 30 | Nov 3 | Nov 9 |
| 20°F | Oct 16 | Oct 22 | Oct 27 | Oct 31 | Nov 3 | Nov 6 | Nov 10 | Nov 14 | Nov 19 |
| 16°F | Oct 26 | Nov 1 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 20 | Nov 23 | Nov 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: Rosette, Ut, about 3.4 miles away@if(!empty($station['elevation_ft'])), at 5,685 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 Malta, UT?
On average, the last spring frost (32°F) around Malta, UT is about May 21. In cooler years it can run later, so for a safer bet many gardeners wait until May 2.
When is the first frost in the fall?
The first fall frost around Malta, UT typically arrives about Oct 2. 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 21 on average, or May 2 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 132 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 84329 Planting calendar → Utah frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026