Frost dates for Coalville, UT
At Coalville, the median last spring frost (32°F) is Jun 7 and the median first fall frost is Sep 12, for a typical growing season of 95 days. For a 90% chance that the last frost has passed, wait until Jun 25. Nearby ZIP codes are in USDA hardiness zones 5b to 6b.
- Jun 7Last spring frost (median)50% chance of 32°F after this date
- Jun 25Safer planting date10% chance of 32°F after this date
- Sep 12First fall frost (median)50% chance of 32°F by this date
- 95 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 32°F | May 21 | Jun 7 | Jun 25 |
| 28°F | May 5 | May 21 | Jun 9 |
| 24°F | Apr 19 | May 3 | May 20 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 32°F | Aug 28 | Sep 12 | Sep 25 |
| 28°F | Sep 9 | Sep 25 | Oct 6 |
| 24°F | Sep 23 | Oct 6 | Oct 23 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 40 days | 66 days | 88 days |
| 32°F | 69 days | 95 days | 118 days |
| 28°F | 99 days | 125 days | 147 days |
| 24°F | 133 days | 154 days | 176 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 84033 | 6a | -10 to -5°F | 11 km |
| 84024 | 6a | -10 to -5°F | 11 km |
| 84017 | 5b | -15 to -10°F | 16 km |
| 84061 | 5b | -15 to -10°F | 18 km |
| 84098 | 5b | -15 to -10°F | 22 km |
| 84050 | 6a | -10 to -5°F | 25 km |
| 84055 | 5b | -15 to -10°F | 28 km |
| 84108 | 6b | -5 to 0°F | 30 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USW00024120, at 40.9139, -111.3983, elevation 1692 m (5,550 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 203.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Echo Dam (6 km)
- Wanship Dam (14 km)
- Coalville 13 E (21 km)
- Morgan (29 km)
- Park City (30 km)
- Kamas (32 km)
- Mountain Dell Dam (33 km)
- Bountiful Bench (38 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.