Killeen, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 13.2 °C (low) to 25.8 °C (high). Annual precipitation averages 864.6 Millimeters. Killeen is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Feb. 21 - Feb. 29 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.7 °C | 15.5 °C | 56.39 mm |
| February | 4.7 °C | 17.6 °C | 57.15 mm |
| March | 8.7 °C | 21.4 °C | 80.52 mm |
| April | 12.8 °C | 25.7 °C | 65.28 mm |
| May | 17.7 °C | 29.3 °C | 117.35 mm |
| June | 21.5 °C | 33.2 °C | 80.52 mm |
| July | 22.8 °C | 35.2 °C | 46.23 mm |
| August | 22.8 °C | 35.8 °C | 63.25 mm |
| September | 19.4 °C | 32.2 °C | 76.96 mm |
| October | 13.7 °C | 26.9 °C | 91.95 mm |
| November | 8 °C | 20.8 °C | 67.31 mm |
| December | 3.7 °C | 16.2 °C | 61.72 mm |
| Annual | 13.2 °C | 25.8 °C | 864.63 mm |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |