San Ramon, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 47.8 °F (low) to 71.5 °F (high). Annual precipitation averages 24.8 Inches. San Ramon is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 11 - Feb. 20 through the first frost around Dec. 21 - Dec. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 39.7 °F | 57.0 °F | 4.79 in. |
| February | 41.3 °F | 60.9 °F | 5.0 in. |
| March | 43.3 °F | 64.8 °F | 3.57 in. |
| April | 45.5 °F | 68.0 °F | 1.8 in. |
| May | 49.6 °F | 73.4 °F | 0.83 in. |
| June | 53.1 °F | 80.5 °F | 0.16 in. |
| July | 56.0 °F | 85.8 °F | 0.02 in. |
| August | 56.3 °F | 85.7 °F | 0.04 in. |
| September | 54.9 °F | 83.9 °F | 0.1 in. |
| October | 50.5 °F | 76.3 °F | 1.13 in. |
| November | 43.8 °F | 65.1 °F | 2.43 in. |
| December | 39.6 °F | 57.1 °F | 4.97 in. |
| Annual | 47.8 °F | 71.5 °F | 24.84 in. |
| Average First Frost Date | Dec. 21 - Dec. 31 |
| Average Last Frost Date | Feb. 11 - Feb. 20 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9b : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |