Harper, Kansas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 46.1 °F (low) to 69.4 °F (high). Annual precipitation averages 32.8 Inches. Harper is located in USDA Plant Hardiness Zone 7a. 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 | 23.0 °F | 44.9 °F | 0.89 in. |
| February | 26.1 °F | 49.3 °F | 1.24 in. |
| March | 35.1 °F | 59.2 °F | 2.34 in. |
| April | 43.9 °F | 68.6 °F | 2.94 in. |
| May | 55.2 °F | 78.0 °F | 4.77 in. |
| June | 65.1 °F | 88.3 °F | 4.72 in. |
| July | 69.6 °F | 93.1 °F | 3.88 in. |
| August | 68.1 °F | 91.4 °F | 3.57 in. |
| September | 59.8 °F | 83.8 °F | 2.68 in. |
| October | 47.0 °F | 71.6 °F | 3.0 in. |
| November | 34.7 °F | 58.0 °F | 1.43 in. |
| December | 25.4 °F | 46.3 °F | 1.31 in. |
| Annual | 46.1 °F | 69.4 °F | 32.77 in. |
| 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 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |