The official National Weather Service forecast for Cynthiana — 38.1875°N, 87.7103°W, 2.1 miles from I-64. Forecasts here are written by NWS PAH, this county’s forecast office.
| Posey County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 41 | 46 | 57 | 68 | 77 | 85 | 88 | 87 | 82 | 70 | 56 | 46 | 67 |
| Avg low °F | 25 | 28 | 37 | 46 | 57 | 65 | 69 | 67 | 59 | 48 | 37 | 29 | 47 |
| Precip in | 3.4 | 3.2 | 4.6 | 5.0 | 4.8 | 4.3 | 4.6 | 3.2 | 3.3 | 3.4 | 3.5 | 3.8 | 47.1 |
1996–2025 normals for Posey County — the climate division Cynthiana sits in. All-time county record high 107.1°F (2012-06-29); record low -15.8°F (1977-01-17). Source: NOAA / National Weather Service.