Frost dates for Helena, AR
At Helena, the median last spring frost (32°F) is Mar 15 and the median first fall frost is Nov 16, for a typical growing season of 246 days. For a 90% chance that the last frost has passed, wait until Apr 1. Nearby ZIP codes are in USDA hardiness zone 8a.
- Mar 15Last spring frost (median)50% chance of 32°F after this date
- Apr 1Safer planting date10% chance of 32°F after this date
- Nov 16First fall frost (median)50% chance of 32°F by this date
- 246 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 10 | Mar 30 | Apr 16 |
| 32°F | Feb 27 | Mar 15 | Apr 1 |
| 28°F | Feb 10 | Mar 3 | Mar 21 |
| 24°F | Jan 21 | Feb 20 | Mar 10 |
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 24 | Nov 5 | Nov 21 |
| 32°F | Nov 2 | Nov 16 | Dec 4 |
| 28°F | Nov 10 | Nov 29 | Dec 19 |
| 24°F | Nov 22 | Dec 15 | 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 | 200 days | 223 days | 245 days |
| 32°F | 222 days | 246 days | 272 days |
| 28°F | 242 days | 270 days | 299 days |
| 24°F | 265 days | 298 days | 327 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 99% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 72390 | 8a | 10 to 15°F | 9 km |
| 72342 | 8a | 10 to 15°F | 11 km |
| 38644 | 8a | 10 to 15°F | 13 km |
| 38626 | 8a | 10 to 15°F | 14 km |
| 38631 | 8a | 10 to 15°F | 18 km |
| 72369 | 8a | 10 to 15°F | 20 km |
| 38617 | 8a | 10 to 15°F | 20 km |
| 72355 | 8a | 10 to 15°F | 25 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 USC00033242, at 34.5211, -90.5900, elevation 59 m (195 ft).
- Data quality: Standard (24+ years of data), 29 years of freeze data.
- Average days per year at or below 32°F: 53.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Marianna 2 S (29 km)
- Saint Charles (52 km)
- Clarendon (68 km)
- Brinkley (70 km)
- West Memphis Muni Airport (76 km)
- Stuttgart 9 ESE (76 km)
- W Memphis (77 km)
- Wynne (84 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.