North Charleston, South Carolina: planting zone & frost dates
North Charleston is in USDA plant hardiness zone 9a, where the average coldest winter night reaches 20 to 25°F (-6.7 to -3.9°C). The typical last spring frost is around Mar 15 and the first fall frost around Nov 19.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Mar 27 | Nov 8 |
| Typical planning date (30% risk) | Mar 15 | Nov 19 |
| Median (50%) | Mar 7 | Nov 27 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station CHARLESTON INTL AP, SC (USW00013880), 1.9 mi (3.1 km) from the city center and 3 ft higher than the city center (+1 m). Record used for the 1991–2020 normals: 30 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across North Charleston
North Charleston spans more than one half-zone. Share of the city's land area by zone (via its 8 ZIP codes): 9a (72%), 8b (28%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
Vegetable planting calendar for North Charleston
Dates are counted from the 30%-risk frost dates above (last frost Mar 15, first frost Nov 19). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Jan 18 – Feb 1 | Mar 22 – Apr 5 | — | — |
| Pepper | Jan 4 – Jan 18 | Mar 29 – Apr 12 | — | — |
| Lettuce | Feb 1 – Feb 15 | Mar 1 – Mar 22 | Feb 15 – Mar 29 | Sep 10 – Oct 8 |
| Green Beans | — | — | Mar 22 – Apr 26 | Aug 27 – Sep 10 |
| Sweet Corn | — | — | Mar 22 – Apr 19 | — |
| Zucchini & Summer Squash | Feb 15 – Feb 22 | Mar 22 – Apr 5 | Mar 22 – Apr 12 | Aug 27 – Sep 10 |
| Cucumber | Feb 15 – Feb 22 | Mar 29 – Apr 5 | Mar 22 – Apr 12 | Aug 27 – Sep 10 |
| Carrot | — | — | Feb 22 – Mar 29 | Aug 27 – Sep 10 |
| Onion | Dec 21 – Jan 4 | Feb 15 – Mar 1 | — | — |
| Potato | — | Feb 15 – Mar 8 | — | — |
| Basil | Feb 1 – Feb 15 | Mar 29 – Apr 12 | Mar 29 – Apr 19 | — |
| Spinach | — | — | Feb 1 – Mar 1 | Sep 24 – Oct 22 |
| Kale | Jan 18 – Feb 1 | Feb 15 – Mar 8 | Feb 15 – Mar 8 | Sep 10 – Oct 8 |
| Broccoli | Jan 18 – Feb 1 | Mar 1 – Mar 22 | — | Aug 27 – Sep 10 |
| Peas | — | — | Feb 1 – Feb 22 | Sep 10 – Sep 24 |
| Eggplant | Jan 4 – Jan 18 | Mar 29 – Apr 12 | — | — |
| Cabbage | Jan 18 – Feb 1 | Feb 15 – Mar 1 | — | Aug 27 – Sep 10 |
| Radish | — | — | Feb 8 – Mar 29 | Oct 8 – Nov 5 |
| Strawberry | — | Feb 15 – Mar 8 | — | — |
| Beets | — | — | Feb 22 – Apr 5 | Sep 10 – Sep 24 |
Nearby cities in South Carolina
- Charleston — zone 9a, last frost Feb 17, first frost Dec 20
- Mount Pleasant — zone 9a, last frost Mar 21, first frost Nov 21
- Columbia — zone 8b, last frost Mar 31, first frost Nov 9
More: all South Carolina cities · other zone 9a cities: San Antonio, TX, Austin, TX, Seattle, WA, Las Vegas, NV, Portland, OR, Tucson, AZ, Baton Rouge, LA, Tallahassee, FL
North Charleston gardening questions
When is the last frost in North Charleston, SC?
Plan around Mar 15. At NOAA's Charleston Int'l Airport, SC station, 1.9 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Mar 7, and after Mar 27 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Feb 20. The 90% and 10% dates are 43 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in North Charleston, SC?
Start seeds indoors Jan 18 – Feb 1 and set transplants outside Mar 22 – Apr 5, once nights stay above 50°F and the soil is near 60°F. That leaves 249 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in North Charleston?
About 266 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 238 days, and in 1 year in 10 it runs 298 days or more. In fall there is a 10% chance of frost by Nov 8 and a 30% chance by Nov 19. That ranks 2nd longest of 4 South Carolina cities on this site.
When should I plant a fall garden in North Charleston?
Count back from the first fall frost (Nov 19): transplant broccoli Aug 27 – Sep 10; sow kale Sep 10 – Oct 8; sow lettuce Sep 10 – Oct 8; sow radishes Oct 8 – Nov 5. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 15. How the math works: succession and fall planting.
Did North Charleston's hardiness zone change on the 2023 map?
Yes. Most of North Charleston was zone 8b on the 2012 map and is zone 9a on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
Is all of North Charleston in zone 9a?
No. Zone 9a covers about 72% of the city's land; the rest is in 8b (28%), measured across the city's 8 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.