Swan Valley, Idaho has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 30 °F (low) to 55.4 °F (high). Annual precipitation averages 20.6 Inches. 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 | 12.0 °F | 29.2 °F | 1.96 in. |
| February | 14.4 °F | 33.4 °F | 1.42 in. |
| March | 22.4 °F | 43.5 °F | 1.64 in. |
| April | 29.1 °F | 53.8 °F | 1.91 in. |
| May | 36.9 °F | 63.8 °F | 2.48 in. |
| June | 43.3 °F | 72.8 °F | 2.11 in. |
| July | 48.8 °F | 83.5 °F | 1.14 in. |
| August | 47.5 °F | 82.6 °F | 1.21 in. |
| September | 40.0 °F | 72.6 °F | 1.62 in. |
| October | 30.9 °F | 57.8 °F | 1.74 in. |
| November | 21.5 °F | 41.6 °F | 1.69 in. |
| December | 13.3 °F | 29.9 °F | 1.65 in. |
| Annual | 30 °F | 55.4 °F | 20.57 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |