| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 24°F | 42°F | 32°F | 3.4" |
| February | 25°F | 44°F | 33°F | 2.6" |
| March | 34°F | 56°F | 44°F | 3.9" |
| April | 43°F | 69°F | 56°F | 4.2" |
| May | 52°F | 76°F | 63°F | 4.1" |
| June | 60°F | 83°F | 71°F | 4.9" |
| July | 64°F | 85°F | 74°F | 4.8" |
| August | 63°F | 86°F | 73°F | 3.6" |
| September | 56°F | 80°F | 67°F | 3.2" |
| October | 45°F | 68°F | 55°F | 3.7" |
| November | 35°F | 57°F | 45°F | 2.9" |
| December | 29°F | 46°F | 37°F | 4.2" |
| Index | Williamstown | West Virginia | National |
| Air quality index | 35 | 126 | 42 |
| Pollution index | 2,805,740 | 1,996,538 | 2,726,193 |
| Measurement | Total |
| Days measured | 364 |
| Days with good air quality | 333 |
| Days with moderate air quality | 31 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.005% |
| Lead | 0.060% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| North Hills, WV | 950 | 35 | 30.0% |
| Newport CDP (Shelby County), OH | 159 | 35 | 30.0% |
| Parkersburg, WV | 29,732 | 35 | 30.0% |
| Belmont, WV | 965 | 35 | 30.0% |
| Lowell, OH | 538 | 35 | 30.0% |
| Williamstown, WV | 2,901 | 35 | 30.0% |
| City | Population | Air Quality Index | National Avg. |
| Pretty Bayou, FL | 2,901 | 38 | 24.0% |
| Port Richey, FL | 2,900 | 43 | 14.0% |
| Butler, AL | 2,902 | 36 | 28.0% |
| Tangelo Park, FL | 2,899 | 39 | 22.0% |
| Poplarville, MS | 2,899 | 35 | 30.0% |
| Williamstown, WV | 2,901 | 35 | 30.0% |
Here are the best places to live in West Virginia
These are the largest cities in West Virginia
Most Dangerous States In The US
Check out the 10 safest cities in West Virginia