Forestville, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.9 °C (low) to 21.7 °C (high). Annual precipitation averages 1201.7 Millimeters. Forestville is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 3.3 °C | 14.2 °C | 256.29 mm |
| February | 4.1 °C | 16.2 °C | 255.02 mm |
| March | 5.1 °C | 18 °C | 156.46 mm |
| April | 5.9 °C | 20.3 °C | 68.58 mm |
| May | 7.8 °C | 23.3 °C | 35.81 mm |
| June | 9.8 °C | 26.7 °C | 11.94 mm |
| July | 10.7 °C | 27.8 °C | 0.51 mm |
| August | 10.8 °C | 28.2 °C | 2.54 mm |
| September | 9.7 °C | 28.1 °C | 4.32 mm |
| October | 7.7 °C | 25.1 °C | 49.78 mm |
| November | 4.8 °C | 18.6 °C | 123.19 mm |
| December | 3 °C | 14.2 °C | 237.24 mm |
| Annual | 6.9 °C | 21.7 °C | 1201.68 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 30-40 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 9a : -6.7°C to -3.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |