The official National Weather Service forecast for Larkspur — 37.9341°N, 122.5353°W, 11.3 miles from I-80. Forecasts here are written by NWS MTR, this county’s forecast office.
| Marin County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 57 | 59 | 61 | 63 | 66 | 70 | 72 | 73 | 73 | 70 | 62 | 56 | 65 |
| Avg low °F | 43 | 44 | 44 | 45 | 48 | 50 | 52 | 53 | 53 | 50 | 46 | 43 | 48 |
| Precip in | 6.4 | 6.6 | 4.5 | 2.2 | 1.0 | 0.2 | 0.0 | 0.0 | 0.2 | 1.8 | 4.1 | 8.0 | 35.0 |
1996–2025 normals for Marin County — the climate division Larkspur sits in. All-time county record high 99.8°F (2022-09-06); record low 21.3°F (1990-12-22). Source: NOAA / National Weather Service.