Dayton, Idaho has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.5 °C (low) to 15.2 °C (high). Annual precipitation averages 431.6 Millimeters. Dayton is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.8 °C | 0.2 °C | 47.5 mm |
| February | -7.9 °C | 2.8 °C | 35.05 mm |
| March | -3.1 °C | 9.2 °C | 40.13 mm |
| April | 0.1 °C | 14.1 °C | 46.23 mm |
| May | 4 °C | 19.3 °C | 57.66 mm |
| June | 7.5 °C | 25.3 °C | 29.21 mm |
| July | 11.6 °C | 31.2 °C | 16.26 mm |
| August | 10.7 °C | 30.4 °C | 22.35 mm |
| September | 6.1 °C | 24.8 °C | 35.05 mm |
| October | 0.6 °C | 16.4 °C | 42.42 mm |
| November | -4.7 °C | 7.7 °C | 29.21 mm |
| December | -8.9 °C | 0.9 °C | 30.48 mm |
| Annual | 0.5 °C | 15.2 °C | 431.55 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |