Swan Valley, Idaho has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.1 °C (low) to 13 °C (high). Annual precipitation averages 522.5 Millimeters. Swan Valley is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Sep.1 - Sep. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.1 °C | -1.6 °C | 49.78 mm |
| February | -9.8 °C | 0.8 °C | 36.07 mm |
| March | -5.3 °C | 6.4 °C | 41.66 mm |
| April | -1.6 °C | 12.1 °C | 48.51 mm |
| May | 2.7 °C | 17.7 °C | 62.99 mm |
| June | 6.3 °C | 22.7 °C | 53.59 mm |
| July | 9.3 °C | 28.6 °C | 28.96 mm |
| August | 8.6 °C | 28.1 °C | 30.73 mm |
| September | 4.4 °C | 22.6 °C | 41.15 mm |
| October | -0.6 °C | 14.3 °C | 44.2 mm |
| November | -5.8 °C | 5.3 °C | 42.93 mm |
| December | -10.4 °C | -1.2 °C | 41.91 mm |
| Annual | -1.1 °C | 13 °C | 522.48 mm |
| Average First Frost Date | Sep.1 - Sep. 10 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | Over 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 | Extreme Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |