Allen, Kansas has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.4 °C (low) to 18.9 °C (high). Annual precipitation averages 924.5 Millimeters. Allen is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.3 °C | 4.4 °C | 22.1 mm |
| February | -5.4 °C | 7.2 °C | 33.53 mm |
| March | 0.1 °C | 13.4 °C | 59.94 mm |
| April | 5.6 °C | 18.9 °C | 88.39 mm |
| May | 12.1 °C | 23.9 °C | 134.87 mm |
| June | 17.4 °C | 29.1 °C | 121.92 mm |
| July | 19.8 °C | 31.9 °C | 114.55 mm |
| August | 18.7 °C | 31.3 °C | 105.66 mm |
| September | 13.9 °C | 26.9 °C | 89.41 mm |
| October | 6.7 °C | 20.2 °C | 70.61 mm |
| November | 0.3 °C | 12.8 °C | 47.24 mm |
| December | -5.1 °C | 6.2 °C | 36.32 mm |
| Annual | 6.4 °C | 18.9 °C | 924.54 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |