Forbestown, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 46.4 °F (low) to 70 °F (high). Annual precipitation averages 64.6 Inches. Forbestown is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 36.3 °F | 54.0 °F | 11.48 in. |
| February | 36.4 °F | 55.5 °F | 10.68 in. |
| March | 38.6 °F | 59.2 °F | 9.91 in. |
| April | 41.3 °F | 64.2 °F | 4.97 in. |
| May | 48.0 °F | 72.4 °F | 2.88 in. |
| June | 54.9 °F | 82.0 °F | 0.9 in. |
| July | 61.1 °F | 90.2 °F | 0.04 in. |
| August | 60.0 °F | 90.1 °F | 0.17 in. |
| September | 55.9 °F | 85.2 °F | 0.42 in. |
| October | 48.2 °F | 73.7 °F | 3.35 in. |
| November | 40.1 °F | 60.3 °F | 6.71 in. |
| December | 35.7 °F | 52.6 °F | 13.05 in. |
| Annual | 46.4 °F | 70 °F | 64.56 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |