The official National Weather Service forecast for Sumter — 33.9204°N, 80.3415°W, population 68,825, 14 miles from I-95. Forecasts here are written by NWS CAE, this county’s forecast office.
| Sumter County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 57 | 61 | 68 | 76 | 83 | 89 | 91 | 90 | 85 | 76 | 67 | 60 | 75 |
| Avg low °F | 34 | 38 | 43 | 51 | 59 | 68 | 71 | 70 | 64 | 53 | 43 | 37 | 53 |
| Precip in | 3.4 | 3.4 | 3.5 | 3.3 | 3.7 | 4.6 | 5.0 | 5.1 | 4.2 | 3.2 | 2.6 | 3.6 | 45.6 |
1996–2025 normals for Sumter County — the climate division Sumter sits in. All-time county record high 105.3°F (1983-08-22); record low 3.6°F (1985-01-21). Source: NOAA / National Weather Service.