Leighton, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.5 °C (low) to 15.7 °C (high). Annual precipitation averages 934.2 Millimeters. Leighton is located in USDA Plant Hardiness Zone 5b. 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 | -10.4 °C | -0.7 °C | 28.19 mm |
| February | -8.4 °C | 1.9 °C | 37.08 mm |
| March | -2.4 °C | 9.2 °C | 53.09 mm |
| April | 4.1 °C | 16.4 °C | 96.77 mm |
| May | 10.7 °C | 22.1 °C | 131.06 mm |
| June | 16.5 °C | 27.6 °C | 126.75 mm |
| July | 18.1 °C | 29.7 °C | 107.7 mm |
| August | 17.1 °C | 28.5 °C | 106.93 mm |
| September | 12 °C | 24.8 °C | 90.17 mm |
| October | 5.2 °C | 18 °C | 67.06 mm |
| November | -1.3 °C | 9.1 °C | 53.59 mm |
| December | -7.3 °C | 2.3 °C | 35.81 mm |
| Annual | 4.5 °C | 15.7 °C | 934.2 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°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 |