Allen, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 12.8 °C (low) to 24.5 °C (high). Annual precipitation averages 1047.2 Millimeters. Allen 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 | 1.4 °C | 13.1 °C | 68.07 mm |
| February | 3.4 °C | 15.4 °C | 75.69 mm |
| March | 7.8 °C | 19.7 °C | 95.5 mm |
| April | 12.1 °C | 24.1 °C | 93.98 mm |
| May | 17.3 °C | 28.1 °C | 129.54 mm |
| June | 21.8 °C | 32.6 °C | 99.57 mm |
| July | 23.8 °C | 35 °C | 54.86 mm |
| August | 23.4 °C | 35.3 °C | 57.66 mm |
| September | 19.4 °C | 31.3 °C | 79.5 mm |
| October | 13.2 °C | 25.8 °C | 119.38 mm |
| November | 7.2 °C | 19 °C | 85.09 mm |
| December | 2.7 °C | 14.1 °C | 88.39 mm |
| Annual | 12.8 °C | 24.5 °C | 1047.23 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 |