The official National Weather Service forecast for Lame Deer — 45.623°N, 106.6667°W, 35.7 miles from I-90.
| Rosebud County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 33 | 35 | 47 | 57 | 67 | 77 | 88 | 86 | 76 | 59 | 45 | 34 | 59 |
| Avg low °F | 10 | 12 | 22 | 31 | 41 | 50 | 57 | 54 | 45 | 32 | 21 | 12 | 32 |
| Precip in | 0.5 | 0.5 | 0.7 | 1.6 | 2.9 | 2.3 | 1.4 | 1.1 | 1.2 | 1.3 | 0.5 | 0.5 | 14.5 |
1996–2025 normals for Rosebud County — the climate division Lame Deer sits in. All-time county record high 111.3°F (2026-07-13); record low -40.0°F (1983-12-24). Source: NOAA / National Weather Service.