San Ramon, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 8.8 °C (low) to 22 °C (high). Annual precipitation averages 630.9 Millimeters. 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 | 4.3 °C | 13.9 °C | 121.67 mm |
| February | 5.2 °C | 16.1 °C | 127 mm |
| March | 6.3 °C | 18.2 °C | 90.68 mm |
| April | 7.5 °C | 20 °C | 45.72 mm |
| May | 9.8 °C | 23 °C | 21.08 mm |
| June | 11.7 °C | 26.9 °C | 4.06 mm |
| July | 13.3 °C | 29.9 °C | 0.51 mm |
| August | 13.5 °C | 29.8 °C | 1.02 mm |
| September | 12.7 °C | 28.8 °C | 2.54 mm |
| October | 10.3 °C | 24.6 °C | 28.7 mm |
| November | 6.6 °C | 18.4 °C | 61.72 mm |
| December | 4.2 °C | 13.9 °C | 126.24 mm |
| Annual | 8.8 °C | 22 °C | 630.94 mm |
| 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 : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |