Forestdale, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.5 °C (low) to 23 °C (high). Annual precipitation averages 1490.5 Millimeters. Forestdale is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.3 °C | 12.1 °C | 133.6 mm |
| February | 2.7 °C | 14.6 °C | 140.72 mm |
| March | 6.6 °C | 19.1 °C | 145.29 mm |
| April | 10.6 °C | 23.4 °C | 130.05 mm |
| May | 15.7 °C | 27.3 °C | 114.05 mm |
| June | 19.9 °C | 30.7 °C | 123.95 mm |
| July | 21.7 °C | 32.3 °C | 130.56 mm |
| August | 21.3 °C | 32.1 °C | 109.98 mm |
| September | 18.2 °C | 29.6 °C | 115.32 mm |
| October | 11.8 °C | 23.9 °C | 87.12 mm |
| November | 5.8 °C | 18 °C | 124.21 mm |
| December | 2.6 °C | 13.4 °C | 135.64 mm |
| Annual | 11.5 °C | 23 °C | 1490.49 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |