Kirwin, Kansas has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4 °C (low) to 19.1 °C (high). Annual precipitation averages 633.2 Millimeters. Kirwin is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.2 °C | 4.5 °C | 13.72 mm |
| February | -7.8 °C | 6.8 °C | 20.07 mm |
| March | -2.6 °C | 13.3 °C | 36.58 mm |
| April | 2.8 °C | 18.7 °C | 53.59 mm |
| May | 9.2 °C | 24 °C | 103.12 mm |
| June | 15.6 °C | 30.4 °C | 81.03 mm |
| July | 18.3 °C | 33.3 °C | 95.25 mm |
| August | 17 °C | 31.7 °C | 81.03 mm |
| September | 11.7 °C | 27.5 °C | 54.36 mm |
| October | 3.7 °C | 20.5 °C | 45.72 mm |
| November | -2.9 °C | 12.4 °C | 26.42 mm |
| December | -8.1 °C | 5.8 °C | 22.35 mm |
| Annual | 4 °C | 19.1 °C | 633.24 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |