Frost dates for Callao, UT
At Callao, the median last spring frost (32°F) is May 14 and the median first fall frost is Sep 28, for a typical growing season of 135 days. For a 90% chance that the last frost has passed, wait until Jun 4. Nearby ZIP codes are in USDA hardiness zones 5b to 7a.
- May 14Last spring frost (median)50% chance of 32°F after this date
- Jun 4Safer planting date10% chance of 32°F after this date
- Sep 28First fall frost (median)50% chance of 32°F by this date
- 135 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 13 | May 31 | Jun 16 |
| 32°F | Apr 29 | May 14 | Jun 4 |
| 28°F | Apr 15 | Apr 30 | May 18 |
| 24°F | Mar 31 | Apr 16 | May 3 |
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 | Oct 1 |
| 32°F | Sep 14 | Sep 28 | Oct 12 |
| 28°F | Sep 25 | Oct 8 | Oct 22 |
| 24°F | Oct 4 | 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 | 89 days | 109 days | 132 days |
| 32°F | 109 days | 135 days | 154 days |
| 28°F | 138 days | 160 days | 180 days |
| 24°F | 161 days | 184 days | 205 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 |
|---|---|---|---|
| 84034 | 6b | -5 to 0°F | 18 km |
| 84728 | 6a | -10 to -5°F | 65 km |
| 89311 | 6b | -5 to 0°F | 82 km |
| 84029 | 7a | 0 to 5°F | 99 km |
| 89301 | 5b | -15 to -10°F | 99 km |
| 84635 | 6a | -10 to -5°F | 102 km |
| 84083 | 6b | -5 to 0°F | 102 km |
| 84022 | 6b | -5 to 0°F | 104 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 USC00421144, at 39.8997, -113.7128, elevation 1323 m (4,342 ft).
- Data quality: Standard (24+ years of data), 25 years of freeze data.
- Average days per year at or below 32°F: 165.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Fish Springs Nwr (28 km)
- Ibapah (28 km)
- Partoun (33 km)
- Granite Peak Dugway Pg (42 km)
- Dugway (74 km)
- Eskdale (90 km)
- Wendover Airport Awos (95 km)
- Johnson Pass (106 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.