The official National Weather Service forecast for La Mesa — 32.7678°N, 117.0231°W, 2.3 miles from I-8. Forecasts here are written by NWS SGX, this county’s forecast office.
| San Diego County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 65 | 65 | 68 | 72 | 78 | 85 | 91 | 92 | 88 | 80 | 71 | 64 | 77 |
| Avg low °F | 41 | 41 | 44 | 46 | 51 | 57 | 63 | 63 | 60 | 52 | 45 | 41 | 50 |
| Precip in | 2.2 | 2.7 | 1.7 | 0.8 | 0.3 | 0.0 | 0.1 | 0.2 | 0.3 | 0.5 | 1.1 | 2.0 | 11.9 |
1996–2025 normals for San Diego County — the climate division La Mesa sits in. All-time county record high 109.4°F (2020-09-07); record low 23.5°F (1968-12-21). Source: NOAA / National Weather Service.