The official National Weather Service forecast for Riverside — 33.6062°N, 86.2044°W, 16.5 miles from I-59. Forecasts here are written by NWS BMX, this county’s forecast office.
| St. Clair County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 54 | 59 | 67 | 74 | 81 | 88 | 90 | 90 | 85 | 76 | 65 | 57 | 74 |
| Avg low °F | 32 | 36 | 42 | 49 | 58 | 66 | 69 | 68 | 62 | 51 | 40 | 35 | 51 |
| Precip in | 5.4 | 5.6 | 5.9 | 5.1 | 4.8 | 5.0 | 4.7 | 4.1 | 3.8 | 3.2 | 3.8 | 5.3 | 56.7 |
1996–2025 normals for St. Clair County — the climate division Riverside sits in. All-time county record high 106.1°F (1952-07-29); record low -5.9°F (1985-01-21). Source: NOAA / National Weather Service.