Frost dates for Helena, AL
At Helena, the median last spring frost (32°F) is Mar 19 and the median first fall frost is Nov 8, for a typical growing season of 236 days. For a 90% chance that the last frost has passed, wait until Apr 9. Nearby ZIP codes are in USDA hardiness zones 8a to 8b.
- Mar 19Last spring frost (median)50% chance of 32°F after this date
- Apr 9Safer planting date10% chance of 32°F after this date
- Nov 8First fall frost (median)50% chance of 32°F by this date
- 236 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 15 | Apr 3 | Apr 21 |
| 32°F | Feb 26 | Mar 19 | Apr 9 |
| 28°F | Feb 8 | Mar 4 | Mar 25 |
| 24°F | Jan 22 | Feb 17 | Mar 12 |
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 17 | Oct 30 | Nov 13 |
| 32°F | Oct 26 | Nov 8 | Nov 29 |
| 28°F | Nov 3 | Nov 22 | Dec 13 |
| 24°F | Nov 13 | Dec 5 | Jan 8 |
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 | 189 days | 210 days | 235 days |
| 32°F | 210 days | 236 days | 261 days |
| 28°F | 235 days | 262 days | 292 days |
| 24°F | 261 days | 294 days | 326 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 |
|---|---|---|---|
| 35114 | 8b | 15 to 20°F | 6 km |
| 35080 | 8a | 10 to 15°F | 8 km |
| 35244 | 8a | 10 to 15°F | 9 km |
| 35124 | 8b | 15 to 20°F | 10 km |
| 35226 | 8b | 15 to 20°F | 14 km |
| 35043 | 8b | 15 to 20°F | 16 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 USC00013781, at 33.2725, -86.8336, elevation 146 m (480 ft).
- Data quality: Representative (10+ years), 17 years of freeze data.
- Average days per year at or below 32°F: 51.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Alabaster Shelby Co Airport (12 km)
- Bessemer 3 WSW (21 km)
- Birmingham Airport (34 km)
- Thorsby Exp. Station (42 km)
- Childersburg Water Plant (46 km)
- Pinson (48 km)
- Clanton 2 NE (51 km)
- Bankhead L&d (53 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.