Frost dates for Ninety Nine Island, SC
At Ninety Nine Island, the median last spring frost (32°F) is Apr 20 and the median first fall frost is Oct 24, for a typical growing season of 186 days. For a 90% chance that the last frost has passed, wait until May 6. Nearby ZIP codes are in USDA hardiness zone 8a.
- Apr 20Last spring frost (median)50% chance of 32°F after this date
- May 6Safer planting date10% chance of 32°F after this date
- Oct 24First fall frost (median)50% chance of 32°F by this date
- 186 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 | Apr 15 | May 1 | May 15 |
| 32°F | Apr 2 | Apr 20 | May 6 |
| 28°F | Mar 20 | Apr 6 | Apr 24 |
| 24°F | Mar 5 | Mar 24 | Apr 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 4 | Oct 15 | Oct 29 |
| 32°F | Oct 11 | Oct 24 | Nov 5 |
| 28°F | Oct 20 | Nov 1 | Nov 16 |
| 24°F | Oct 30 | Nov 12 | Dec 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 | 148 days | 168 days | 188 days |
| 32°F | 165 days | 186 days | 209 days |
| 28°F | 187 days | 210 days | 233 days |
| 24°F | 210 days | 234 days | 262 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 |
|---|---|---|---|
| 29743 | 8a | 10 to 15°F | 6 km |
| 29702 | 8a | 10 to 15°F | 10 km |
| 29717 | 8a | 10 to 15°F | 10 km |
| 29340 | 8a | 10 to 15°F | 11 km |
| 29341 | 8a | 10 to 15°F | 22 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 USC00386293, at 35.0317, -81.4928, elevation 152 m (500 ft).
- Data quality: Standard (24+ years of data), 25 years of freeze data.
- Average days per year at or below 32°F: 93.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- York 5 SSE (30 km)
- Rock Hill York Co Airport (40 km)
- Spartanburg 3 SSE (41 km)
- Winthrop Univ (43 km)
- Chesnee 7 WSW (44 km)
- Santuck (44 km)
- Chester 1 SE (47 km)
- Union 8 S (50 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.
All South Carolina stations · How frost dates are calculated