The official National Weather Service forecast for Box Elder — 44.1125°N, 103.0682°W, population 11,386, 0.4 miles from I-90.
| Pennington County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 35 | 37 | 48 | 56 | 66 | 78 | 86 | 85 | 76 | 61 | 48 | 37 | 59 |
| Avg low °F | 13 | 13 | 23 | 31 | 41 | 51 | 58 | 56 | 47 | 34 | 23 | 14 | 34 |
| Precip in | 0.4 | 0.6 | 1.0 | 2.2 | 3.4 | 3.0 | 2.5 | 1.9 | 1.4 | 1.5 | 0.5 | 0.5 | 18.9 |
1996–2025 normals for Pennington County — the climate division Box Elder sits in. All-time county record high 107.8°F (2006-07-16); record low -31.1°F (1989-12-22). Source: NOAA / National Weather Service.