The official National Weather Service forecast for Thompson Falls — 47.5949°N, 115.3383°W, 15 miles from I-90.
| Sanders County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 32 | 35 | 44 | 52 | 62 | 70 | 81 | 80 | 69 | 53 | 38 | 31 | 54 |
| Avg low °F | 20 | 20 | 25 | 30 | 37 | 44 | 50 | 49 | 42 | 33 | 25 | 20 | 33 |
| Precip in | 3.6 | 3.1 | 3.2 | 2.4 | 2.6 | 2.4 | 0.8 | 1.0 | 1.5 | 2.9 | 4.0 | 4.1 | 31.6 |
1996–2025 normals for Sanders County — the climate division Thompson Falls sits in. All-time county record high 99.7°F (2018-08-11); record low -29.7°F (1968-12-31). Source: NOAA / National Weather Service.