Killen, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 49.4 °F (low) to 71.6 °F (high). Annual precipitation averages 58.7 Inches. Killen 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 | 30.1 °F | 50.5 °F | 5.33 in. |
| February | 33.2 °F | 54.9 °F | 5.44 in. |
| March | 40.1 °F | 63.5 °F | 5.68 in. |
| April | 48.4 °F | 72.5 °F | 4.98 in. |
| May | 57.4 °F | 79.7 °F | 5.09 in. |
| June | 65.4 °F | 86.5 °F | 4.61 in. |
| July | 68.8 °F | 89.4 °F | 5.15 in. |
| August | 67.5 °F | 88.9 °F | 4.31 in. |
| September | 61.2 °F | 84.2 °F | 4.14 in. |
| October | 49.0 °F | 74.0 °F | 3.92 in. |
| November | 38.3 °F | 62.2 °F | 4.1 in. |
| December | 33.0 °F | 53.1 °F | 5.97 in. |
| Annual | 49.4 °F | 71.6 °F | 58.72 in. |
| 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 : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |