Shelby, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.5 °C (low) to 24 °C (high). Annual precipitation averages 1425.4 Millimeters. Shelby 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 | 13.3 °C | 134.62 mm |
| February | 2.3 °C | 15.8 °C | 142.49 mm |
| March | 5.8 °C | 20.1 °C | 138.18 mm |
| April | 9.4 °C | 24.3 °C | 127.76 mm |
| May | 14.4 °C | 28.2 °C | 105.16 mm |
| June | 18.8 °C | 31.4 °C | 119.63 mm |
| July | 20.7 °C | 33.1 °C | 122.17 mm |
| August | 20.2 °C | 32.7 °C | 106.68 mm |
| September | 17.1 °C | 30.3 °C | 98.04 mm |
| October | 10.3 °C | 24.9 °C | 82.8 mm |
| November | 4.5 °C | 18.9 °C | 112.78 mm |
| December | 1.9 °C | 14.4 °C | 135.13 mm |
| Annual | 10.5 °C | 24 °C | 1425.44 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 |