The official National Weather Service forecast for Hartsville — 34.374°N, 80.0734°W, population 13,946, 12.5 miles from I-20. Forecasts here are written by NWS ILM, this county’s forecast office.
| Darlington County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 56 | 60 | 68 | 76 | 83 | 89 | 92 | 90 | 85 | 76 | 67 | 59 | 75 |
| Avg low °F | 33 | 37 | 43 | 50 | 59 | 67 | 71 | 70 | 64 | 52 | 42 | 36 | 52 |
| Precip in | 3.4 | 3.3 | 3.5 | 3.3 | 3.9 | 4.3 | 5.3 | 5.1 | 5.0 | 3.1 | 2.7 | 3.6 | 46.5 |
1996–2025 normals for Darlington County — the climate division Hartsville sits in. All-time county record high 105.3°F (1983-08-22); record low -0.0°F (1985-01-21). Source: NOAA / National Weather Service.