Montclair, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 52.4 °F (low) to 78.1 °F (high). Annual precipitation averages 16.1 Inches. Montclair is located in USDA Plant Hardiness Zone 10a.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 44.0 °F | 67.1 °F | 3.59 in. |
| February | 44.7 °F | 67.5 °F | 4.23 in. |
| March | 46.9 °F | 70.6 °F | 2.64 in. |
| April | 49.3 °F | 74.5 °F | 0.76 in. |
| May | 53.5 °F | 78.1 °F | 0.42 in. |
| June | 57.3 °F | 84.2 °F | 0.11 in. |
| July | 62.0 °F | 90.7 °F | 0.06 in. |
| August | 62.9 °F | 92.7 °F | 0.02 in. |
| September | 61.0 °F | 89.7 °F | 0.13 in. |
| October | 55.3 °F | 81.6 °F | 0.7 in. |
| November | 48.1 °F | 73.8 °F | 0.93 in. |
| December | 43.6 °F | 66.2 °F | 2.55 in. |
| Annual | 52.4 °F | 78.1 °F | 16.14 in. |
| Average First Frost Date | No Frost |
| Average Last Frost Date | |
| Average Days With Frost | Frost Free |
| 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 |