The official National Weather Service forecast for Mount Shasta — 41.3102°N, 122.3123°W, population 5,203, 5 miles from I-5. Forecasts here are written by NWS MFR, this county’s forecast office.
| Siskiyou County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 44 | 46 | 51 | 57 | 66 | 75 | 85 | 84 | 76 | 63 | 49 | 42 | 62 |
| Avg low °F | 28 | 28 | 30 | 33 | 39 | 46 | 53 | 52 | 47 | 38 | 32 | 28 | 38 |
| Precip in | 6.0 | 5.2 | 4.7 | 2.8 | 1.9 | 0.8 | 0.3 | 0.3 | 0.7 | 2.4 | 4.7 | 7.2 | 37.0 |
1996–2025 normals for Siskiyou County — the climate division Mount Shasta sits in. All-time county record high 102.3°F (2022-07-30); record low -8.8°F (1972-12-09). Source: NOAA / National Weather Service.