Dayton, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.2 °C (low) to 14.6 °C (high). Annual precipitation averages 914.2 Millimeters. Dayton is located in USDA Plant Hardiness Zone 5a. 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 | -12.3 °C | -2.5 °C | 23.11 mm |
| February | -10.1 °C | 0 °C | 28.96 mm |
| March | -3.6 °C | 7.4 °C | 52.07 mm |
| April | 2.6 °C | 15.5 °C | 95.25 mm |
| May | 9.6 °C | 21.6 °C | 128.02 mm |
| June | 15.4 °C | 26.9 °C | 137.16 mm |
| July | 17.4 °C | 28.7 °C | 109.22 mm |
| August | 15.9 °C | 27.4 °C | 112.01 mm |
| September | 11 °C | 24.3 °C | 82.04 mm |
| October | 4 °C | 17.1 °C | 67.31 mm |
| November | -2.8 °C | 8.1 °C | 44.2 mm |
| December | -8.8 °C | 0.5 °C | 34.8 mm |
| Annual | 3.2 °C | 14.6 °C | 914.15 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |