Gardendale, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.8 °C (low) to 23.1 °C (high). Annual precipitation averages 1481.8 Millimeters. Gardendale is located in USDA Plant Hardiness Zone 8a. 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 | 0.5 °C | 12.1 °C | 135.13 mm |
| February | 2 °C | 14.5 °C | 135.13 mm |
| March | 5.8 °C | 19.1 °C | 145.54 mm |
| April | 9.9 °C | 23.5 °C | 132.33 mm |
| May | 14.9 °C | 27.3 °C | 118.87 mm |
| June | 19.3 °C | 30.7 °C | 120.9 mm |
| July | 21.2 °C | 32.4 °C | 128.27 mm |
| August | 20.8 °C | 32.1 °C | 107.44 mm |
| September | 17.5 °C | 29.6 °C | 113.28 mm |
| October | 10.9 °C | 24 °C | 87.38 mm |
| November | 5 °C | 18 °C | 119.89 mm |
| December | 2 °C | 13.4 °C | 137.67 mm |
| Annual | 10.8 °C | 23.1 °C | 1481.83 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |