The official National Weather Service forecast for Joliet — 45.4852°N, 108.9704°W, 9.6 miles from I-90.
| Carbon County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 34 | 35 | 45 | 52 | 61 | 71 | 81 | 79 | 69 | 55 | 43 | 34 | 55 |
| Avg low °F | 15 | 15 | 22 | 29 | 38 | 46 | 53 | 51 | 44 | 33 | 23 | 16 | 32 |
| Precip in | 0.8 | 1.1 | 1.2 | 1.9 | 2.8 | 2.2 | 1.1 | 1.1 | 1.4 | 1.7 | 0.9 | 0.9 | 17.1 |
1996–2025 normals for Carbon County — the climate division Joliet sits in. All-time county record high 102.7°F (2026-07-13); record low -33.4°F (1964-12-17). Source: NOAA / National Weather Service.