Forbestown, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 8 °C (low) to 21.1 °C (high). Annual precipitation averages 1639.8 Millimeters. 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 | 2.4 °C | 12.2 °C | 291.59 mm |
| February | 2.4 °C | 13.1 °C | 271.27 mm |
| March | 3.7 °C | 15.1 °C | 251.71 mm |
| April | 5.2 °C | 17.9 °C | 126.24 mm |
| May | 8.9 °C | 22.4 °C | 73.15 mm |
| June | 12.7 °C | 27.8 °C | 22.86 mm |
| July | 16.2 °C | 32.3 °C | 1.02 mm |
| August | 15.6 °C | 32.3 °C | 4.32 mm |
| September | 13.3 °C | 29.6 °C | 10.67 mm |
| October | 9 °C | 23.2 °C | 85.09 mm |
| November | 4.5 °C | 15.7 °C | 170.43 mm |
| December | 2.1 °C | 11.4 °C | 331.47 mm |
| Annual | 8 °C | 21.1 °C | 1639.82 mm |
| 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 : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |