Swannanoa, North Carolina has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 6.7 °C (low) to 19.5 °C (high). Annual precipitation averages 1220.2 Millimeters. Swannanoa is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.1 °C | 8.7 °C | 99.57 mm |
| February | -1.8 °C | 10.6 °C | 83.06 mm |
| March | 1.6 °C | 14.7 °C | 104.39 mm |
| April | 5.8 °C | 20 °C | 105.66 mm |
| May | 10.5 °C | 23.9 °C | 109.73 mm |
| June | 15 °C | 27.4 °C | 114.3 mm |
| July | 16.9 °C | 29.1 °C | 116.33 mm |
| August | 16.4 °C | 28.4 °C | 108.97 mm |
| September | 13 °C | 25.5 °C | 113.54 mm |
| October | 6.8 °C | 20.5 °C | 79.5 mm |
| November | 1.1 °C | 14.9 °C | 85.6 mm |
| December | -1.4 °C | 10.3 °C | 99.57 mm |
| Annual | 6.7 °C | 19.5 °C | 1220.22 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |