Gannett, Idaho has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from -1 °C (low) to 14.5 °C (high). Annual precipitation averages 311.9 Millimeters. Gannett is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.7 °C | -0.1 °C | 41.91 mm |
| February | -10 °C | 2.3 °C | 29.21 mm |
| March | -5.4 °C | 7.6 °C | 32.26 mm |
| April | -1.4 °C | 13.5 °C | 27.69 mm |
| May | 2.9 °C | 18.9 °C | 35.31 mm |
| June | 6.2 °C | 24 °C | 21.08 mm |
| July | 10.2 °C | 30.4 °C | 7.11 mm |
| August | 9.4 °C | 29.8 °C | 8.13 mm |
| September | 5.1 °C | 24.2 °C | 13.72 mm |
| October | -0.7 °C | 16.1 °C | 25.15 mm |
| November | -5.9 °C | 6.9 °C | 25.4 mm |
| December | -10.8 °C | 0.2 °C | 44.96 mm |
| Annual | -1 °C | 14.5 °C | 311.93 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |