Mount Hermon, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 45.4 °F (low) to 72.6 °F (high). Annual precipitation averages 46.3 Inches. Mount Hermon is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 39.4 °F | 60.5 °F | 9.17 in. |
| February | 40.6 °F | 62.2 °F | 9.76 in. |
| March | 41.9 °F | 65.4 °F | 6.07 in. |
| April | 43.3 °F | 71.1 °F | 3.02 in. |
| May | 46.5 °F | 76.0 °F | 1.12 in. |
| June | 49.1 °F | 80.2 °F | 0.25 in. |
| July | 52.3 °F | 83.4 °F | 0.03 in. |
| August | 52.2 °F | 84.2 °F | 0.07 in. |
| September | 50.6 °F | 83.8 °F | 0.18 in. |
| October | 47.1 °F | 79.1 °F | 1.88 in. |
| November | 42.8 °F | 66.2 °F | 4.51 in. |
| December | 39.1 °F | 59.3 °F | 10.19 in. |
| Annual | 45.4 °F | 72.6 °F | 46.25 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |