The official National Weather Service forecast for Ottawa — 41.0192°N, 84.0472°W, population 5,418, 12.7 miles from I-75.
| Putnam County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 34 | 37 | 49 | 62 | 72 | 82 | 84 | 83 | 78 | 65 | 51 | 39 | 61 |
| Avg low °F | 19 | 22 | 30 | 39 | 50 | 60 | 63 | 62 | 55 | 44 | 33 | 25 | 42 |
| Precip in | 2.4 | 2.3 | 2.7 | 3.6 | 4.4 | 4.0 | 4.1 | 3.6 | 2.9 | 2.7 | 2.5 | 2.6 | 37.8 |
1996–2025 normals for Putnam County — the climate division Ottawa sits in. All-time county record high 103.9°F (2012-06-29); record low -20.9°F (1994-01-19). Source: NOAA / National Weather Service.