Haddam, Kansas has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.5 °C (low) to 18.1 °C (high). Annual precipitation averages 774.2 Millimeters. Haddam 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.3 °C | 3.1 °C | 16.76 mm |
| February | -6.4 °C | 5.6 °C | 24.64 mm |
| March | -1 °C | 12.3 °C | 41.91 mm |
| April | 4.5 °C | 18.1 °C | 71.63 mm |
| May | 11 °C | 23.6 °C | 113.79 mm |
| June | 16.8 °C | 29.3 °C | 112.27 mm |
| July | 19.4 °C | 31.9 °C | 109.22 mm |
| August | 18.1 °C | 30.7 °C | 90.68 mm |
| September | 12.9 °C | 26.7 °C | 74.93 mm |
| October | 5.9 °C | 19.8 °C | 56.64 mm |
| November | -1.1 °C | 11.5 °C | 34.8 mm |
| December | -6.2 °C | 4.8 °C | 26.92 mm |
| Annual | 5.5 °C | 18.1 °C | 774.19 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 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 |