San Rafael, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 48.1 °F (low) to 69.5 °F (high). Annual precipitation averages 39.7 Inches. San Rafael is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 42.1 °F | 56.3 °F | 8.06 in. |
| February | 43.6 °F | 60.2 °F | 8.18 in. |
| March | 44.8 °F | 63.3 °F | 5.31 in. |
| April | 46.4 °F | 67.6 °F | 2.39 in. |
| May | 49.2 °F | 72.5 °F | 1.14 in. |
| June | 52.0 °F | 77.8 °F | 0.25 in. |
| July | 53.6 °F | 80.1 °F | 0.0 in. |
| August | 54.2 °F | 80.4 °F | 0.05 in. |
| September | 53.2 °F | 80.0 °F | 0.09 in. |
| October | 50.2 °F | 74.6 °F | 1.74 in. |
| November | 45.7 °F | 64.0 °F | 3.92 in. |
| December | 41.9 °F | 56.6 °F | 8.54 in. |
| Annual | 48.1 °F | 69.5 °F | 39.67 in. |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 9b : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 10a : 30°F to 25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |