| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 28°F | 44°F | 36°F | 5.1" |
| February | 22°F | 40°F | 31°F | 3.6" |
| March | 34°F | 54°F | 43°F | 4.9" |
| April | 41°F | 66°F | 53°F | 4.8" |
| May | 49°F | 75°F | 62°F | 5.7" |
| June | 60°F | 85°F | 72°F | 3.5" |
| July | 63°F | 84°F | 73°F | 8.1" |
| August | 66°F | 87°F | 75°F | 5.1" |
| September | 56°F | 83°F | 68°F | 1.6" |
| October | 48°F | 71°F | 58°F | 5.0" |
| November | 36°F | 58°F | 46°F | 6.5" |
| December | 28°F | 44°F | 35°F | 8.2" |
| Index | Grafton | West Virginia | National |
| Air quality index | 31 | 126 | 42 |
| Pollution index | 323,222 | 1,996,538 | 2,726,193 |
| Measurement | Total |
| Days measured | 99 |
| Days with good air quality | 87 |
| Days with moderate air quality | 12 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.004% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.003% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Anmoore, WV | 702 | 31 | 38.0% |
| Carolina, WV | 313 | 31 | 38.0% |
| White Hall, WV | 1,216 | 31 | 38.0% |
| Philippi, WV | 3,310 | 31 | 38.0% |
| Enterprise, WV | 1,115 | 31 | 38.0% |
| Grafton, WV | 5,035 | 31 | 38.0% |
| City | Population | Air Quality Index | National Avg. |
| Crestwood, KY | 5,034 | 49 | 2.0% |
| Polson, MT | 5,033 | 37 | 26.0% |
| Archer Lodge, NC | 5,037 | 46 | 8.0% |
| Olyphant, PA | 5,037 | 38 | 24.0% |
| Rainsville, AL | 5,038 | 39 | 22.0% |
| Grafton, WV | 5,035 | 31 | 38.0% |
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