Frost dates for Bullfrog Basin, UT
At Bullfrog Basin, the median last spring frost (32°F) is Mar 25 and the median first fall frost is Nov 10, for a typical growing season of 227 days. For a 90% chance that the last frost has passed, wait until Apr 12. Nearby ZIP codes are in USDA hardiness zone 8a.
- Mar 25Last spring frost (median)50% chance of 32°F after this date
- Apr 12Safer planting date10% chance of 32°F after this date
- Nov 10First fall frost (median)50% chance of 32°F by this date
- 227 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 | Mar 25 | Apr 11 | Apr 30 |
| 32°F | Mar 8 | Mar 25 | Apr 12 |
| 28°F | Feb 18 | Mar 6 | Mar 22 |
| 24°F | Jan 27 | Feb 20 | Mar 7 |
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 16 | Oct 31 | Nov 12 |
| 32°F | Oct 26 | Nov 10 | Nov 20 |
| 28°F | Nov 7 | Nov 20 | Dec 2 |
| 24°F | Nov 19 | Nov 29 | Dec 16 |
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 | 176 days | 199 days | 219 days |
| 32°F | 204 days | 227 days | 247 days |
| 28°F | 235 days | 255 days | 277 days |
| 24°F | 260 days | 282 days | 310 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 |
|---|---|---|---|
| 84533 | 8a | 10 to 15°F | 21 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 USC00421020, at 37.5269, -110.7167, elevation 1165 m (3,822 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 95.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Hite Ranger Station (48 km)
- Natural Bridges National Monument (66 km)
- Boulder (75 km)
- Valley Of The Gods (75 km)
- Escalante (82 km)
- Mexican Hat (86 km)
- Hans Flat Ranger Station (94 km)
- Hanksville (94 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.