Frost dates for Castleford 2 N, ID
At Castleford 2 N, the median last spring frost (32°F) is May 17 and the median first fall frost is Sep 29, for a typical growing season of 132 days. For a 90% chance that the last frost has passed, wait until Jun 5. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- May 17Last spring frost (median)50% chance of 32°F after this date
- Jun 5Safer planting date10% chance of 32°F after this date
- Sep 29First fall frost (median)50% chance of 32°F by this date
- 132 daysGrowing season (median)between 32°F freezes
USDA hardiness zone 7a (0 to 5°F) · see all zone 7a frost dates
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 18 | Jun 5 | Jun 20 |
| 32°F | Apr 30 | May 17 | Jun 5 |
| 28°F | Apr 14 | Apr 30 | May 18 |
| 24°F | Mar 25 | Apr 13 | May 1 |
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 1 | Sep 16 | Oct 1 |
| 32°F | Sep 11 | Sep 29 | Oct 15 |
| 28°F | Sep 26 | Oct 13 | Oct 28 |
| 24°F | Oct 8 | Oct 26 | Nov 10 |
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 | 80 days | 103 days | 125 days |
| 32°F | 108 days | 132 days | 154 days |
| 28°F | 137 days | 162 days | 184 days |
| 24°F | 168 days | 193 days | 218 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 |
|---|---|---|---|
| 83316 | 7a | 0 to 5°F | 8 km |
| 83321 | 6b | -5 to 0°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 USC00101551, at 42.5503, -114.8661, elevation 1166 m (3,825 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 146.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Buhl #2 (11 km)
- Hagerman 2 SW (29 km)
- Twin Falls Sun Valley Regional Airport (32 km)
- Twin Falls-Kmvt (34 km)
- Jerome (35 km)
- Jerome Co Airport (39 km)
- Twin Falls 6 E (43 km)
- Shoshone 1 WNW (57 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.