Preston, Idaho has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.7 °C (low) to 15.4 °C (high). Annual precipitation averages 435.6 Millimeters. Preston 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 | 0.3 °C | 42.42 mm |
| February | -7.9 °C | 3 °C | 35.81 mm |
| March | -2.9 °C | 9.4 °C | 39.62 mm |
| April | 0.3 °C | 14.3 °C | 43.69 mm |
| May | 4.3 °C | 19.6 °C | 55.63 mm |
| June | 7.8 °C | 25.6 °C | 30.99 mm |
| July | 11.7 °C | 31.3 °C | 23.37 mm |
| August | 10.9 °C | 30.6 °C | 27.94 mm |
| September | 6.2 °C | 24.9 °C | 33.27 mm |
| October | 0.7 °C | 16.7 °C | 41.15 mm |
| November | -4.3 °C | 7.9 °C | 30.23 mm |
| December | -8.8 °C | 1.2 °C | 31.5 mm |
| Annual | 0.7 °C | 15.4 °C | 435.62 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 |