| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 20°F | 35°F | 27°F | 2.3" |
| February | 20°F | 37°F | 28°F | 2.3" |
| March | 31°F | 51°F | 40°F | 3.2" |
| April | 41°F | 64°F | 52°F | 4.1" |
| May | 51°F | 74°F | 63°F | 4.3" |
| June | 61°F | 82°F | 71°F | 4.8" |
| July | 63°F | 85°F | 74°F | 3.5" |
| August | 61°F | 83°F | 72°F | 3.9" |
| September | 54°F | 78°F | 65°F | 2.7" |
| October | 44°F | 66°F | 54°F | 2.9" |
| November | 34°F | 53°F | 43°F | 2.7" |
| December | 26°F | 40°F | 33°F | 3.1" |
| Index | Columbus Grove | Ohio | National |
| Air quality index | 39 | 40 | 42 |
| Pollution index | 2,019,850 | 4,472,386 | 2,726,193 |
| Measurement | Total |
| Days measured | 364 |
| Days with good air quality | 303 |
| Days with moderate air quality | 61 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.003% |
| Lead | 0.010% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Glandorf, OH | 1,215 | 39 | 22.0% |
| Mount Cory, OH | 339 | 39 | 22.0% |
| Vaughnsville, OH | 279 | 39 | 22.0% |
| Harrod, OH | 412 | 39 | 22.0% |
| Ada, OH | 5,427 | 39 | 22.0% |
| Columbus Grove, OH | 1,808 | 39 | 22.0% |
| City | Population | Air Quality Index | National Avg. |
| Saticoy, CA | 1,808 | 46 | 8.0% |
| Elizabeth, CO | 1,808 | 58 | 16.0% |
| Haubstadt, IN | 1,808 | 45 | 10.0% |
| Westwood, KS | 1,808 | 47 | 6.0% |
| Smackover, AR | 1,809 | 35 | 30.0% |
| Columbus Grove, OH | 1,808 | 39 | 22.0% |