The official National Weather Service forecast for Hartsville — 39.2675°N, 85.698°W, 11.7 miles from I-74. Forecasts here are written by NWS IND, this county’s forecast office.
| Bartholomew County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 38 | 43 | 54 | 66 | 75 | 83 | 85 | 85 | 80 | 68 | 54 | 43 | 64 |
| Avg low °F | 22 | 25 | 33 | 42 | 53 | 61 | 65 | 63 | 56 | 45 | 34 | 27 | 44 |
| Precip in | 3.5 | 3.0 | 4.1 | 4.8 | 5.2 | 5.2 | 4.5 | 3.4 | 3.3 | 3.4 | 3.3 | 3.6 | 47.3 |
1996–2025 normals for Bartholomew County — the climate division Hartsville sits in. All-time county record high 103.4°F (2012-06-29); record low -23.2°F (1994-01-19). Source: NOAA / National Weather Service.