Preston, Idaho has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.2 °F (low) to 59.7 °F (high). Annual precipitation averages 17.2 Inches. 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 | 14.4 °F | 32.6 °F | 1.67 in. |
| February | 17.7 °F | 37.4 °F | 1.41 in. |
| March | 26.8 °F | 49.0 °F | 1.56 in. |
| April | 32.6 °F | 57.7 °F | 1.72 in. |
| May | 39.8 °F | 67.2 °F | 2.19 in. |
| June | 46.0 °F | 78.0 °F | 1.22 in. |
| July | 53.1 °F | 88.3 °F | 0.92 in. |
| August | 51.7 °F | 87.1 °F | 1.1 in. |
| September | 43.1 °F | 76.9 °F | 1.31 in. |
| October | 33.2 °F | 62.0 °F | 1.62 in. |
| November | 24.2 °F | 46.3 °F | 1.19 in. |
| December | 16.1 °F | 34.1 °F | 1.24 in. |
| Annual | 33.2 °F | 59.7 °F | 17.15 in. |
| 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 : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |