Mount Pleasant, South Carolina: planting zone & frost dates
Mount Pleasant 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 21 and the first fall frost around Nov 21.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Mar 30 | Nov 11 |
| Typical planning date (30% risk) | Mar 21 | Nov 21 |
| Median (50%) | Mar 13 | Nov 30 |
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 SULLIVANS IS, SC (USC00388405), 3.2 mi (5.2 km) from the city center and 10 ft lower than the city center (-3 m). Record used for the 1991–2020 normals: 24 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Mount Pleasant
All 3 ZIP codes covering Mount Pleasant are in zone 9a.
Vegetable planting calendar for Mount Pleasant
Dates are counted from the 30%-risk frost dates above (last frost Mar 21, first frost Nov 21). 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 24 – Feb 7 | Mar 28 – Apr 11 | — | — |
| Pepper | Jan 10 – Jan 24 | Apr 4 – Apr 18 | — | — |
| Lettuce | Feb 7 – Feb 21 | Mar 7 – Mar 28 | Feb 21 – Apr 4 | Sep 12 – Oct 10 |
| Green Beans | — | — | Mar 28 – May 2 | Aug 29 – Sep 12 |
| Sweet Corn | — | — | Mar 28 – Apr 25 | — |
| Zucchini & Summer Squash | Feb 21 – Feb 28 | Mar 28 – Apr 11 | Mar 28 – Apr 18 | Aug 29 – Sep 12 |
| Cucumber | Feb 21 – Feb 28 | Apr 4 – Apr 11 | Mar 28 – Apr 18 | Aug 29 – Sep 12 |
| Carrot | — | — | Feb 28 – Apr 4 | Aug 29 – Sep 12 |
| Onion | Dec 27 – Jan 10 | Feb 21 – Mar 7 | — | — |
| Potato | — | Feb 21 – Mar 14 | — | — |
| Basil | Feb 7 – Feb 21 | Apr 4 – Apr 18 | Apr 4 – Apr 25 | — |
| Spinach | — | — | Feb 7 – Mar 7 | Sep 26 – Oct 24 |
| Kale | Jan 24 – Feb 7 | Feb 21 – Mar 14 | Feb 21 – Mar 14 | Sep 12 – Oct 10 |
| Broccoli | Jan 24 – Feb 7 | Mar 7 – Mar 28 | — | Aug 29 – Sep 12 |
| Peas | — | — | Feb 7 – Feb 28 | Sep 12 – Sep 26 |
| Eggplant | Jan 10 – Jan 24 | Apr 4 – Apr 18 | — | — |
| Cabbage | Jan 24 – Feb 7 | Feb 21 – Mar 7 | — | Aug 29 – Sep 12 |
| Radish | — | — | Feb 14 – Apr 4 | Oct 10 – Nov 7 |
| Strawberry | — | Feb 21 – Mar 14 | — | — |
| Beets | — | — | Feb 28 – Apr 11 | Sep 12 – Sep 26 |
Nearby cities in South Carolina
- Charleston — zone 9a, last frost Feb 17, first frost Dec 20
- North Charleston — zone 9a, last frost Mar 15, first frost Nov 19
- 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
Mount Pleasant gardening questions
When is the last frost in Mount Pleasant, SC?
Plan around Mar 21. At NOAA's Sullivans Island, SC station, 3.2 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 13, and after Mar 30 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Mar 1. The 90% and 10% dates are 39 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Mount Pleasant, SC?
Start seeds indoors Jan 24 – Feb 7 and set transplants outside Mar 28 – Apr 11, once nights stay above 50°F and the soil is near 60°F. That leaves 245 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 Mount Pleasant?
About 262 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 232 days, and in 1 year in 10 it runs 291 days or more. In fall there is a 10% chance of frost by Nov 11 and a 30% chance by Nov 21. That ranks 3rd longest of 4 South Carolina cities on this site.
When should I plant a fall garden in Mount Pleasant?
Count back from the first fall frost (Nov 21): transplant broccoli Aug 29 – Sep 12; sow kale Sep 12 – Oct 10; sow lettuce Sep 12 – Oct 10; sow radishes Oct 10 – Nov 7. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 16. How the math works: succession and fall planting.
Did Mount Pleasant's hardiness zone change on the 2023 map?
Yes. Most of Mount Pleasant 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.
How does Mount Pleasant compare with Charleston, SC?
Both are in zone 9a. The typical last spring frost in Mount Pleasant (Mar 21) comes about 32 days later than in Charleston, SC (Feb 17), 6 miles away, and the first fall frost is Nov 21 versus Dec 20. The two cities use different NOAA stations.