Citing the freezing temperatures, Berkeley and Charleston county will delay the start of the school day Thursday.
Officials in Dorchester and Colleton counties said Wednesday they did not plan to postpone opening.
Late Wednesday night, the National Weather Service reported light snow in Dorchester, Berkeley and Charleston counties.
Dorchester 2 issued a statement that said, "All staff members will take necessary measures to ensure that students are safe and warm during the school day with no outside activities during the morning hours."
Charleston County will open schools, including the morning Kaleidoscope program, two hours late, according to a news release. Teachers and administrators should report one hour later than usual.
All half-day programs, including child development, SAIL, special needs and Lowcountry Tech, are canceled.
Berkeley schools will start three hours late. After-school childcare and programming is not affected.
The early morning forecast for inland areas Thursday is in the upper teens, said meteorologist Pete Mohlin of the National Weather Service in Charleston. Combined with north winds blowing at 10 to 20 miles per hour, the wind chill temperature could be 5 to 10 degrees, he said.
Along the coast, it will be in the low 20s.
Temperatures will be cold enough to allow frostbite to set in on exposed skin in 30 minutes. Each district encouraged parents to make sure students wear coats, hats and gloves.
Temperatures will not increase much during the day, topping out in the mid-30s, he said. It's likely to stay below freezing until early afternoon.
Winds will die down during the day, so although the temperature is likely to dip into the low 20s Thursday night, it should not be as cold Friday morning, he said.