Demopolis, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.4 °C (low) to 24.2 °C (high). Annual precipitation averages 1404.4 Millimeters. Demopolis is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.3 °C | 13.6 °C | 139.45 mm |
| February | 3 °C | 15.9 °C | 135.38 mm |
| March | 6.4 °C | 20.5 °C | 136.65 mm |
| April | 10.8 °C | 24.6 °C | 122.94 mm |
| May | 15.6 °C | 28.7 °C | 101.09 mm |
| June | 19.9 °C | 31.7 °C | 107.7 mm |
| July | 21.4 °C | 33 °C | 135.89 mm |
| August | 21.2 °C | 32.8 °C | 123.19 mm |
| September | 18 °C | 30.6 °C | 87.38 mm |
| October | 11.3 °C | 25.2 °C | 82.8 mm |
| November | 5.1 °C | 19.2 °C | 104.14 mm |
| December | 2.4 °C | 14.7 °C | 127.76 mm |
| Annual | 11.4 °C | 24.2 °C | 1404.37 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |