The official National Weather Service forecast for Roy — 41.1616°N, 112.0263°W, 0.6 miles from I-15. Forecasts here are written by NWS SLC, this county’s forecast office.
| Weber County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 35 | 38 | 48 | 55 | 65 | 76 | 85 | 83 | 73 | 59 | 46 | 35 | 58 |
| Avg low °F | 18 | 20 | 27 | 33 | 41 | 49 | 57 | 55 | 47 | 36 | 27 | 19 | 36 |
| Precip in | 3.4 | 2.9 | 2.9 | 2.8 | 2.6 | 1.3 | 0.6 | 1.2 | 1.5 | 2.2 | 2.3 | 3.3 | 27.0 |
1996–2025 normals for Weber County — the climate division Roy sits in. All-time county record high 99.0°F (2026-07-13); record low -25.5°F (1982-02-06). Source: NOAA / National Weather Service.