| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 20°F | 39°F | 29°F | 3.4" |
| February | 22°F | 42°F | 31°F | 1.4" |
| March | 32°F | 56°F | 42°F | 2.6" |
| April | 41°F | 69°F | 54°F | 3.1" |
| May | 53°F | 77°F | 64°F | 3.2" |
| June | 60°F | 84°F | 71°F | 4.4" |
| July | 64°F | 86°F | 74°F | 5.4" |
| August | 61°F | 86°F | 72°F | 5.0" |
| September | 54°F | 79°F | 65°F | 2.7" |
| October | 43°F | 68°F | 54°F | 2.4" |
| November | 32°F | 56°F | 42°F | 4.6" |
| December | 27°F | 44°F | 35°F | 4.0" |
| Index | Gallipolis | Ohio | National |
| Air quality index | 42 | 40 | 42 |
| Pollution index | 2,383,860 | 4,472,386 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 299 |
| Days with moderate air quality | 66 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.004% |
| Lead | 0.120% |
| Mercury | 0.020% |
| City | Population | Air Quality Index | National Avg. |
| Rio Grande, OH | 1,087 | 14 | 72.0% |
| Pomeroy, OH | 1,821 | 25 | 50.0% |
| Mason, WV | 738 | 25 | 50.0% |
| Point Pleasant, WV | 4,197 | 25 | 50.0% |
| Syracuse, OH | 766 | 25 | 50.0% |
| Gallipolis, OH | 3,646 | 42 | 16.0% |
| City | Population | Air Quality Index | National Avg. |
| Kimberly, AL | 3,646 | 53 | 6.0% |
| Lincoln Park, CO | 3,645 | 16 | 68.0% |
| Dahlgren, VA | 3,645 | 47 | 6.0% |
| Dennis Port, MA | 3,647 | 36 | 28.0% |
| Roselawn, IN | 3,644 | 37 | 26.0% |
| Gallipolis, OH | 3,646 | 42 | 16.0% |