The official National Weather Service forecast for Helena — 41.3412°N, 83.2916°W, 8.1 miles from I-90.
| Sandusky County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 34 | 37 | 48 | 60 | 71 | 81 | 84 | 82 | 77 | 64 | 50 | 39 | 61 |
| Avg low °F | 20 | 22 | 30 | 39 | 50 | 60 | 64 | 62 | 55 | 45 | 34 | 26 | 42 |
| Precip in | 2.3 | 2.2 | 2.6 | 3.5 | 3.8 | 3.8 | 3.8 | 3.6 | 3.1 | 2.8 | 2.4 | 2.4 | 36.3 |
1996–2025 normals for Sandusky County — the climate division Helena sits in. All-time county record high 101.8°F (1988-06-26); record low -19.4°F (1994-01-19). Source: NOAA / National Weather Service.