Calvert, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 12.3 °C (low) to 24.9 °C (high). Annual precipitation averages 1638.8 Millimeters. Calvert is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.6 °C | 15.3 °C | 154.43 mm |
| February | 3.6 °C | 17.4 °C | 129.54 mm |
| March | 6.7 °C | 21.3 °C | 140.97 mm |
| April | 10.3 °C | 25 °C | 125.22 mm |
| May | 17.3 °C | 29 °C | 123.44 mm |
| June | 19.3 °C | 32 °C | 166.62 mm |
| July | 22.6 °C | 32.3 °C | 170.18 mm |
| August | 22.2 °C | 32.2 °C | 150.88 mm |
| September | 19.9 °C | 30.2 °C | 125.98 mm |
| October | 13.6 °C | 26.4 °C | 92.2 mm |
| November | 7.5 °C | 20.8 °C | 115.57 mm |
| December | 2.9 °C | 16.7 °C | 143.76 mm |
| Annual | 12.3 °C | 24.9 °C | 1638.79 mm |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 20-30 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 |