Charleston, SC 29403 Frost Dates
29403, near Charleston, SC: the frost window
Around 02/04 is the usual last spring frost, about 160 days away. Fall's first freeze usually shows up around 12/30, roughly 321 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Charleston in Zone 9a (20 to 25°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Charleston's growing season runs out in roughly 18 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
02/04 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 03/04 and only about 1 year in 10 sees frost after that.
Charleston against the rest of the dataset
At roughly 321 frost-free days, Charleston places 3,288 of 40,283 ZIP codes in this dataset. Within SC, it ranks 1 of 519.
Learn more
Two guides worth reading on 29403: local microclimates, on what one yard in Charleston can differ from the 29403 normal, and zone vs. frost date, on why Zone 9a and Charleston's frost date answer different questions.