Sumter, South Carolina Weather
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Climate of Sumter: monthly averages
Based on 25 years of satellite and reanalysis data (2001-2025), July is usually the hottest month in Sumter, with average daytime highs around 33°C. January is the coolest, when nights typically fall to about 1°C and frost is possible on the coldest nights. That is a wide yearly range of roughly 33°C, so the seasons feel very different from each other.
The area receives about 1150 mm of rain in a typical year. Most of it falls from June to August and December, and July is the wettest month at roughly 127 mm.
For outdoor plans and travel, March to May and September to November usually offer the most comfortable weather in Sumter, with mild days and relatively little rain.
| Month | Avg high | Avg low | Rainfall | Humidity |
|---|---|---|---|---|
| Jan | 12° | 1° | 71 mm | 80% |
| Feb | 14° | 2° | 88 mm | 80% |
| Mar | 19° | 6° | 87 mm | 78% |
| Apr | 24° | 11° | 78 mm | 74% |
| May | 28° | 17° | 98 mm | 71% |
| Jun | 32° | 21° | 120 mm | 69% |
| Jul | 33° | 23° | 127 mm | 69% |
| Aug | 33° | 22° | 120 mm | 71% |
| Sep | 30° | 19° | 99 mm | 71% |
| Oct | 25° | 12° | 86 mm | 72% |
| Nov | 19° | 6° | 73 mm | 72% |
| Dec | 14° | 3° | 101 mm | 79% |
Source: NASA POWER (MERRA-2 reanalysis), averaged over the roughly 50 km grid area around Sumter. Values describe typical conditions, not a forecast.
About Sumter weather
Sumter, in South Carolina's humid subtropical climate, coastal and low-lying for much of the state, is positioned about 65 km east of Columbia. The warmer months mean hot, humid summers (June–August) with highs commonly in the low-to-mid 30s°C. Finally, there's mild winters (December–February), rarely dropping below freezing near the coast. This page shows live, auto-refreshing weather for Sumter: current conditions, an hourly breakdown, a 16-day outlook, a date-lookup tool for any past or future date, and real-time air quality, sourced from Open-Meteo. Local timezone: America/New_York.
Frequently asked questions
Sumter is about 65 km east of Columbia, in South Carolina.
Sumter sees mild winters (December–February), rarely dropping below freezing near the coast.
The live current conditions, hourly forecast and 16-day outlook above are pulled in real time for Sumter's exact coordinates. No fixed schedule, the page updates whenever you load it.
July is usually the hottest month in Sumter, with average daytime highs of about 33°C and nights around 23°C.
The coldest nights come in January, when the average low is about 1°C and daytime highs reach around 12°C. Frost is possible on clear, calm nights.
Sumter receives about 1150 mm of rain in a typical year. July is the wettest month at roughly 127 mm, and the main rainy period is June to August and December.
March to May and September to November usually offer the most comfortable weather in Sumter, with mild daytime temperatures and little rain.
In November Sumter typically sees daytime highs near 19°C and lows near 6°C, with about 73 mm of rain over the month and average humidity around 72%. Check the live forecast above for this week's actual conditions.
Up to 16 days ahead using the extended forecast and date picker above; further-out or historical dates use the same date lookup tool.
The current temperature for Sumter updates automatically at the top of this page — scroll to the hourly strip below to see how it's expected to change over the day.
Sumter's day-to-day weather follows the broader pattern of South Carolina described above. See the hourly weather forecast or the air quality index for more detail.