| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 27°F | 44°F | 35°F | 3.0" |
| February | 27°F | 46°F | 35°F | 2.1" |
| March | 36°F | 56°F | 45°F | 3.8" |
| April | 46°F | 68°F | 56°F | 4.4" |
| May | 53°F | 74°F | 63°F | 4.5" |
| June | 61°F | 81°F | 70°F | 3.9" |
| July | 64°F | 82°F | 72°F | 5.0" |
| August | 64°F | 82°F | 72°F | 3.7" |
| September | 57°F | 76°F | 66°F | 2.9" |
| October | 47°F | 67°F | 56°F | 3.3" |
| November | 37°F | 57°F | 46°F | 2.5" |
| December | 31°F | 48°F | 39°F | 3.6" |
| Index | Welch | West Virginia | National |
| Air quality index | 295 | 126 | 42 |
| Pollution index | 655,580 | 1,996,538 | 2,726,193 |
| Measurement | Total |
| Days measured | 120 |
| Days with good air quality | 106 |
| Days with moderate air quality | 14 |
| Days w/ poor A.Q. for sensitive groups | |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.100% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.003% |
| Lead | 0.010% |
| Mercury | 0.005% |
| City | Population | Air Quality Index | National Avg. |
| Berwind, WV | 225 | 295 | 490.0% |
| War, WV | 666 | 295 | 490.0% |
| Iaeger, WV | 274 | 295 | 490.0% |
| Gary, WV | 665 | 295 | 490.0% |
| Itmann, WV | 213 | 295 | 490.0% |
| Welch, WV | 2,943 | 295 | 490.0% |
| City | Population | Air Quality Index | National Avg. |
| Eufaula, OK | 2,943 | 43 | 14.0% |
| Cetronia, PA | 2,943 | 42 | 16.0% |
| Chincoteague, VA | 2,943 | 36 | 28.0% |
| Good Hope, AL | 2,942 | 41 | 18.0% |
| Elgin, SC | 2,942 | 49 | 2.0% |
| Welch, WV | 2,943 | 295 | 490.0% |