Frost dates for Castle Valley, UT
At Castle Valley, the median last spring frost (32°F) is Apr 17 and the median first fall frost is Oct 23, for a typical growing season of 185 days. For a 90% chance that the last frost has passed, wait until May 3. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- Apr 17Last spring frost (median)50% chance of 32°F after this date
- May 3Safer planting date10% chance of 32°F after this date
- Oct 23First fall frost (median)50% chance of 32°F by this date
- 185 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 | Apr 14 | Apr 30 | May 14 |
| 32°F | Apr 1 | Apr 17 | May 3 |
| 28°F | Mar 14 | Apr 4 | Apr 20 |
| 24°F | Feb 26 | Mar 16 | Apr 8 |
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 | Oct 1 | Oct 14 | Oct 27 |
| 32°F | Oct 9 | Oct 23 | Nov 5 |
| 28°F | Oct 17 | Nov 1 | Nov 15 |
| 24°F | Oct 26 | Nov 10 | Nov 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 | 145 days | 166 days | 184 days |
| 32°F | 165 days | 185 days | 208 days |
| 28°F | 187 days | 210 days | 233 days |
| 24°F | 212 days | 237 days | 263 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 |
|---|---|---|---|
| 84532 | 7a | 0 to 5°F | 15 km |
| 84515 | 6b | -5 to 0°F | 29 km |
| 81522 | 6b | -5 to 0°F | 42 km |
| 84530 | 7a | 0 to 5°F | 45 km |
| 81523 | 6b | -5 to 0°F | 54 km |
| 81429 | 6b | -5 to 0°F | 54 km |
| 81411 | 6b | -5 to 0°F | 58 km |
| 84540 | 6b | -5 to 0°F | 64 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 USC00421241, at 38.6514, -109.3986, elevation 1440 m (4,725 ft).
- Data quality: Representative (10+ years), 14 years of freeze data.
- Average days per year at or below 32°F: 120.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Castle Valley 1se (3 km)
- Moab (15 km)
- Arches National Park Hqs (20 km)
- Dewey (20 km)
- Moab Canyonland Airport (33 km)
- La Sal 1sw (41 km)
- Canyonlands-The Neck (42 km)
- Canyonlands-The Needles (62 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.