Johnston, SC Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Johnston, a town in Edgefield County, South Carolina.
Today
79°F
Periods Of Rain Showers then Slight Chance T-storms
Periods of rain showers before 2pm, then a slight chance of thunderstorms and a slight chance of rain. Cloudy, with a high near 79. Southeast wind around 10 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Johnston
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 79°F | Periods Of Rain Showers then Slight Chance T-storms | 10 mph SE | 20% |
| Tonight | 64°F | Slight Chance T-storms then Light Rain Likely | 5 to 10 mph S | 61% |
| Thursday | 79°F | Patchy Fog then Slight Chance Light Rain | 3 to 7 mph SW | 20% |
| Thursday Night | 62°F | Mostly Cloudy then Chance Light Rain | 2 mph S | 45% |
| Friday | 77°F | Chance Light Rain | 2 to 7 mph SW | 53% |
| Friday Night | 52°F | Mostly Clear | 5 mph NW | 6% |
| Saturday | 72°F | Sunny | 7 mph N | 1% |
| Saturday Night | 44°F | Partly Cloudy | 5 mph NE | 1% |
| Sunday | 68°F | Mostly Sunny | 5 mph NE | 2% |
| Sunday Night | 42°F | Mostly Clear | 3 mph N | 2% |
| Monday | 68°F | Sunny | 5 mph N | 1% |
| Monday Night | 41°F | Mostly Clear | 2 mph W | 2% |
| Tuesday | 70°F | Sunny | 1 to 6 mph W | 4% |
| Tuesday Night | 43°F | Mostly Clear | 3 mph W | 5% |
Forecast source: National Weather Service (api.weather.gov) for Johnston (33.833, -81.805). Updated through the day.
Growing snapshot for Johnston
Last spring frost
Mar 26
First fall frost
Nov 8
Growing season
228 days
Hardiness zone
8a
More local growing data for Johnston: nearby ZIP 29832 weather · frost dates · planting calendar · South Carolina frost dates
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Climate data from the nearest NOAA station, Johnston 4 Sw, Sc (5 mi from Johnston). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.