Frost dates for Mammoth Spring, AR
At Mammoth Spring, the median last spring frost (32°F) is Apr 12 and the median first fall frost is Oct 24, for a typical growing season of 194 days. For a 90% chance that the last frost has passed, wait until Apr 27. Nearby ZIP codes are in USDA hardiness zone 7a.
- Apr 12Last spring frost (median)50% chance of 32°F after this date
- Apr 27Safer planting date10% chance of 32°F after this date
- Oct 24First fall frost (median)50% chance of 32°F by this date
- 194 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 | Apr 9 | Apr 24 | May 6 |
| 32°F | Mar 27 | Apr 12 | Apr 27 |
| 28°F | Mar 13 | Apr 1 | Apr 16 |
| 24°F | Feb 28 | Mar 18 | Apr 5 |
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 3 | Oct 16 | Oct 26 |
| 32°F | Oct 11 | Oct 24 | Nov 5 |
| 28°F | Oct 21 | Nov 3 | Nov 20 |
| 24°F | Oct 31 | Nov 13 | Dec 2 |
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 | 154 days | 174 days | 192 days |
| 32°F | 174 days | 194 days | 216 days |
| 28°F | 195 days | 217 days | 241 days |
| 24°F | 215 days | 238 days | 264 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 |
|---|---|---|---|
| 72554 | 7a | 0 to 5°F | 6 km |
| 65791 | 7a | 0 to 5°F | 10 km |
| 65692 | 7a | 0 to 5°F | 17 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 USC00034572, at 36.4947, -91.5350, elevation 153 m (502 ft).
- Data quality: Standard (24+ years of data), 26 years of freeze data.
- Average days per year at or below 32°F: 102.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Hardy (25 km)
- Salem (29 km)
- Evening Shade 1 NNE (47 km)
- Pocahontas 1 (57 km)
- Calico Rock 2 WSW (71 km)
- Alicia 2NNE (76 km)
- Batesville Lvstk (77 km)
- Batesville 8 WNW (78 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.