The official National Weather Service forecast for Marysville — 40.2364°N, 83.3671°W, population 25,674, 18.7 miles from I-70.
| Union County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 35 | 39 | 50 | 63 | 73 | 81 | 84 | 83 | 77 | 65 | 51 | 40 | 62 |
| Avg low °F | 20 | 22 | 30 | 40 | 51 | 60 | 63 | 61 | 54 | 43 | 33 | 26 | 42 |
| Precip in | 2.6 | 2.4 | 3.1 | 3.9 | 4.4 | 4.3 | 4.0 | 3.4 | 3.1 | 2.8 | 2.6 | 2.9 | 39.5 |
1996–2025 normals for Union County — the climate division Marysville sits in. All-time county record high 102.3°F (1988-06-26); record low -23.3°F (1994-01-19). Source: NOAA / National Weather Service.