Grantville, Kansas has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.9 °C (low) to 18.7 °C (high). Annual precipitation averages 955.3 Millimeters. Grantville is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.1 °C | 3.8 °C | 23.11 mm |
| February | -4.8 °C | 6.6 °C | 33.27 mm |
| March | 0.6 °C | 13 °C | 58.67 mm |
| April | 6.3 °C | 18.8 °C | 98.81 mm |
| May | 12.7 °C | 24.1 °C | 136.14 mm |
| June | 18.3 °C | 29.3 °C | 130.3 mm |
| July | 20.5 °C | 31.8 °C | 106.68 mm |
| August | 19.3 °C | 31.1 °C | 113.03 mm |
| September | 14.1 °C | 26.9 °C | 92.2 mm |
| October | 7.2 °C | 20.2 °C | 74.17 mm |
| November | 0.6 °C | 12.4 °C | 49.28 mm |
| December | -4.8 °C | 5.8 °C | 39.62 mm |
| Annual | 6.9 °C | 18.7 °C | 955.28 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 |