San Dimas, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 52.8 °F (low) to 78 °F (high). Annual precipitation averages 17.6 Inches. San Dimas is located in USDA Plant Hardiness Zone 10a.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 44.9 °F | 67.5 °F | 3.86 in. |
| February | 45.4 °F | 67.9 °F | 4.75 in. |
| March | 47.4 °F | 70.8 °F | 2.84 in. |
| April | 49.7 °F | 74.5 °F | 0.84 in. |
| May | 53.7 °F | 78.0 °F | 0.38 in. |
| June | 57.4 °F | 83.5 °F | 0.13 in. |
| July | 61.8 °F | 90.0 °F | 0.09 in. |
| August | 62.7 °F | 92.1 °F | 0.01 in. |
| September | 61.0 °F | 89.4 °F | 0.14 in. |
| October | 55.7 °F | 81.7 °F | 0.7 in. |
| November | 49.0 °F | 74.0 °F | 0.98 in. |
| December | 44.4 °F | 66.6 °F | 2.84 in. |
| Annual | 52.8 °F | 78 °F | 17.56 in. |
| Average First Frost Date | No Frost |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 10a : 30°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 10a : 30°F to 25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |