The official National Weather Service forecast for Dunkirk — 40.7564°N, 86.3936°W, 30.5 miles from I-65. Forecasts here are written by NWS IWX, this county’s forecast office.
| Cass County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 33 | 37 | 50 | 62 | 73 | 82 | 84 | 82 | 78 | 65 | 51 | 38 | 61 |
| Avg low °F | 18 | 21 | 30 | 39 | 50 | 60 | 63 | 61 | 54 | 43 | 33 | 24 | 41 |
| Precip in | 2.5 | 2.3 | 2.9 | 3.8 | 4.3 | 4.7 | 4.6 | 3.9 | 2.9 | 3.1 | 2.7 | 2.7 | 40.4 |
1996–2025 normals for Cass County — the climate division Dunkirk sits in. All-time county record high 102.3°F (1980-07-16); record low -22.7°F (1985-01-20). Source: NOAA / National Weather Service.