The official National Weather Service forecast for Mountain House — 37.7833°N, 121.5427°W, 2.9 miles from I-205. Forecasts here are written by NWS STO, this county’s forecast office.
| San Joaquin County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 57 | 62 | 67 | 73 | 81 | 89 | 94 | 93 | 89 | 79 | 66 | 57 | 76 |
| Avg low °F | 39 | 41 | 44 | 47 | 52 | 57 | 60 | 60 | 57 | 51 | 43 | 39 | 49 |
| Precip in | 2.8 | 2.5 | 1.9 | 1.2 | 0.5 | 0.1 | 0.0 | 0.0 | 0.1 | 0.8 | 1.6 | 2.9 | 14.4 |
1996–2025 normals for San Joaquin County — the climate division Mountain House sits in. All-time county record high 112.5°F (2022-09-07); record low 17.5°F (1990-12-22). Source: NOAA / National Weather Service.