Frost dates for Castle Dale, UT
At Castle Dale, the median last spring frost (32°F) is May 18 and the median first fall frost is Sep 27, for a typical growing season of 128 days. For a 90% chance that the last frost has passed, wait until Jun 8. Nearby ZIP codes are in USDA hardiness zone 6a.
- May 18Last spring frost (median)50% chance of 32°F after this date
- Jun 8Safer planting date10% chance of 32°F after this date
- Sep 27First fall frost (median)50% chance of 32°F by this date
- 128 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 |
|---|---|---|---|
| 36°F | May 19 | Jun 3 | Jun 19 |
| 32°F | May 4 | May 18 | Jun 8 |
| 28°F | Apr 22 | May 4 | May 20 |
| 24°F | Apr 9 | Apr 23 | May 6 |
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 |
|---|---|---|---|
| 36°F | Sep 4 | Sep 18 | Sep 28 |
| 32°F | Sep 14 | Sep 27 | Oct 9 |
| 28°F | Sep 25 | Oct 5 | Oct 20 |
| 24°F | Oct 2 | Oct 18 | Nov 1 |
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 | 86 days | 105 days | 124 days |
| 32°F | 108 days | 128 days | 149 days |
| 28°F | 133 days | 153 days | 171 days |
| 24°F | 157 days | 175 days | 194 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 84513 | 6a | -10 to -5°F | 6 km |
| 84537 | 6a | -10 to -5°F | 17 km |
| 84528 | 6a | -10 to -5°F | 22 km |
| 84518 | 6a | -10 to -5°F | 23 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 USC00421214, at 39.2078, -111.0128, elevation 1716 m (5,629 ft).
- Data quality: Representative (10+ years), 24 years of freeze data.
- Average days per year at or below 32°F: 186.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Ferron (17 km)
- Wellington 3 E (47 km)
- Electric Lake (47 km)
- Salina 24 E (48 km)
- Price Carbon Co Airport (50 km)
- Ephraim (53 km)
- Manti (54 km)
- Scofield-Skyline Mine (55 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.