The official National Weather Service forecast for Norco — 33.9311°N, 117.5487°W, 2.2 miles from I-15. Forecasts here are written by NWS SGX, this county’s forecast office.
| Riverside County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 65 | 67 | 73 | 79 | 87 | 96 | 101 | 101 | 95 | 84 | 73 | 64 | 82 |
| Avg low °F | 42 | 43 | 47 | 52 | 59 | 67 | 74 | 73 | 68 | 57 | 48 | 42 | 56 |
| Precip in | 1.3 | 1.5 | 0.9 | 0.4 | 0.1 | 0.0 | 0.2 | 0.3 | 0.3 | 0.3 | 0.5 | 1.1 | 6.9 |
1996–2025 normals for Riverside County — the climate division Norco sits in. All-time county record high 114.5°F (2016-06-21); record low 22.5°F (1968-12-22). Source: NOAA / National Weather Service.