Chelsea, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.8 °C (low) to 23.5 °C (high). Annual precipitation averages 1484.4 Millimeters. Chelsea 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. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.7 °C | 12.7 °C | 132.59 mm |
| February | 2.3 °C | 15.3 °C | 140.72 mm |
| March | 5.9 °C | 19.6 °C | 140.72 mm |
| April | 9.8 °C | 24 °C | 133.1 mm |
| May | 14.9 °C | 27.7 °C | 113.28 mm |
| June | 19.2 °C | 30.9 °C | 127 mm |
| July | 21 °C | 32.6 °C | 125.98 mm |
| August | 20.5 °C | 32.3 °C | 112.52 mm |
| September | 17.3 °C | 30 °C | 114.55 mm |
| October | 10.8 °C | 24.6 °C | 87.63 mm |
| November | 4.8 °C | 18.6 °C | 116.33 mm |
| December | 2.1 °C | 14 °C | 139.95 mm |
| Annual | 10.8 °C | 23.5 °C | 1484.37 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°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 |