Sumter County Climate

Sumter County, South Carolina

JanFebMarAprMayJunJulAugSepOctNovDec63.2°AVG °F

Avg Annual Temp

63.2°F

Annual Precip

47.5"

Annual Snowfall

0.6"

Extreme Heat Days

55.55

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
3.8"
3.6"
3.8"
3.2"
3.5"
5.3"
5.1"
4.9"
3.9"
3.6"
3.0"
3.9"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Seasonal Overview

Comfort ZoneSpring55°70°10.5"Summer77°80°15.3"Fall54°74°10.5"Winter45°48°11.2"20°40°60°80°100°

National Comparison

Warmer than 78% of US counties
Wetter than 65% of US counties
More seasonal variation than 14% of US counties

Climate Profile

About Sumter County Weather

Warm and Sunny Midlands Climate

Sumter County averages 63.2°F annually, which is roughly 9 degrees higher than the U.S. median. Precipitation is consistent with the region at 47.5 inches per year. The humid subtropical climate ensures a long outdoor season and very mild winters.

Right in Line With State Averages

Sumter's annual average of 63.2°F is nearly identical to the South Carolina average of 62.8°F. Its rainfall of 47.5 inches is also very close to the state's 48.9-inch average. Sumter represents the quintessential climate of the South Carolina inner coastal plain.

Slightly Cooler Than its Neighbors

Sumter is slightly cooler than Richland (63.9°F) and Orangeburg (65.3°F) to the west and south. Interestingly, it has fewer extreme heat days (56) than both Richland (84) and Orangeburg (80). This provides a marginally more tempered summer experience than neighboring counties.

Hot Summers and Very Rare Snow

Summers are hot with 56 days reaching 90°F or more and a July average of 80.3°F. Snow is almost a non-factor, averaging only 0.6 inches per year. Winters are pleasant and mild, with temperatures averaging 47.0°F during the winter months.

Prioritize Sun Protection and AC

With 56 days of high heat, maintaining a reliable cooling system and using sun protection is vital. Residents only need light winter gear for the 45.2°F January average, as 0.6 inches of snow rarely impacts travel. The 47.5 inches of rain is well-distributed, but gardeners should plan for summer dry spells.

Frequently Asked Questions

What is the average temperature in Sumter County?
The average annual temperature in Sumter County, SC is 63.2°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Sumter County get?
Sumter County receives an average of 47.5 inches of precipitation per year, including both rain and meltwater from snow. This is based on NOAA 30-year climate normals.
Does it snow in Sumter County?
Yes, Sumter County receives an average of 0.6 inches of snowfall per year according to NOAA climate normals.
How hot does Sumter County get in summer?
The average summer temperature (June-August) in Sumter County is 78.8°F. The county experiences an average of 55.55 days per year above 90°F.
How cold are winters in Sumter County?
The average winter temperature (December-February) in Sumter County is 47.0°F. January, typically the coldest month, averages 45.2°F.

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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.

Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.

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