Herkimer, Kansas has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.4 °F (low) to 64.2 °F (high). Annual precipitation averages 32.4 Inches. Herkimer 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 | 16.3 °F | 36.8 °F | 0.75 in. |
| February | 20.0 °F | 41.6 °F | 1.05 in. |
| March | 30.1 °F | 53.6 °F | 2.0 in. |
| April | 40.0 °F | 64.1 °F | 3.09 in. |
| May | 51.6 °F | 74.2 °F | 4.76 in. |
| June | 62.1 °F | 84.1 °F | 4.6 in. |
| July | 66.4 °F | 88.7 °F | 4.38 in. |
| August | 63.9 °F | 87.2 °F | 3.49 in. |
| September | 54.4 °F | 79.8 °F | 3.25 in. |
| October | 41.8 °F | 67.4 °F | 2.41 in. |
| November | 29.9 °F | 52.5 °F | 1.43 in. |
| December | 20.3 °F | 40.4 °F | 1.18 in. |
| Annual | 41.4 °F | 64.2 °F | 32.39 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |