| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 26°F | 51°F | 37°F | 4.0" |
| February | 28°F | 54°F | 39°F | 2.8" |
| March | 35°F | 62°F | 48°F | 3.6" |
| April | 43°F | 72°F | 57°F | 4.3" |
| May | 51°F | 77°F | 64°F | 3.9" |
| June | 60°F | 84°F | 71°F | 4.7" |
| July | 63°F | 85°F | 73°F | 5.3" |
| August | 63°F | 85°F | 73°F | 5.0" |
| September | 57°F | 80°F | 67°F | 4.6" |
| October | 44°F | 71°F | 56°F | 4.0" |
| November | 34°F | 61°F | 46°F | 3.6" |
| December | 31°F | 54°F | 41°F | 5.3" |
| Index | Swannanoa | North Carolina | National |
| Air quality index | 44 | 35 | 42 |
| Pollution index | 3,495,600 | 2,789,538 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 285 |
| Days with moderate air quality | 78 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.080% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.060% |
| Mercury | 0.040% |
| City | Population | Air Quality Index | National Avg. |
| Fletcher, NC | 8,533 | 44 | 12.0% |
| Weaverville, NC | 4,102 | 44 | 12.0% |
| Biltmore Forest, NC | 1,725 | 44 | 12.0% |
| Old Fort, NC | 769 | 44 | 12.0% |
| Fruitland, NC | 2,263 | 44 | 12.0% |
| Swannanoa, NC | 4,534 | 44 | 12.0% |
| City | Population | Air Quality Index | National Avg. |
| Esperance, WA | 4,534 | 45 | 10.0% |
| Beecher, IL | 4,532 | 55 | 10.0% |
| Dilley, TX | 4,532 | 49 | 2.0% |
| West Jefferson, OH | 4,536 | 46 | 8.0% |
| Skyline View, PA | 4,531 | 44 | 12.0% |
| Swannanoa, NC | 4,534 | 44 | 12.0% |