| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 18°F | 35°F | 26°F | 3.0" |
| February | 17°F | 36°F | 27°F | 2.5" |
| March | 27°F | 49°F | 37°F | 2.9" |
| April | 38°F | 64°F | 50°F | 3.7" |
| May | 48°F | 75°F | 61°F | 3.6" |
| June | 58°F | 84°F | 70°F | 4.2" |
| July | 61°F | 86°F | 73°F | 4.5" |
| August | 60°F | 84°F | 71°F | 3.8" |
| September | 53°F | 78°F | 65°F | 3.4" |
| October | 42°F | 66°F | 53°F | 2.6" |
| November | 32°F | 52°F | 41°F | 3.0" |
| December | 23°F | 39°F | 31°F | 2.9" |
| Index | Delta | Ohio | National |
| Air quality index | 39 | 40 | 42 |
| Pollution index | 2,339,740 | 4,472,386 | 2,726,193 |
| Measurement | Total |
| Days measured | 358 |
| Days with good air quality | 286 |
| Days with moderate air quality | 72 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.020% |
| Mercury | 0.020% |
| City | Population | Air Quality Index | National Avg. |
| Morenci, MI | 2,010 | 39 | 22.0% |
| Pettisville, OH | 558 | 39 | 22.0% |
| Ridgeville Corners, OH | 303 | 39 | 22.0% |
| Tedrow, OH | 216 | 39 | 22.0% |
| Lyons, OH | 677 | 39 | 22.0% |
| Delta, OH | 2,900 | 39 | 22.0% |
| City | Population | Air Quality Index | National Avg. |
| Moose Lake, MN | 2,900 | 35 | 30.0% |
| Towanda, PA | 2,899 | 36 | 28.0% |
| Woodbury, TN | 2,899 | 25 | 50.0% |
| South Padre Island, TX | 2,899 | 44 | 12.0% |
| Holualoa, HI | 2,901 | 16 | 68.0% |
| Delta, OH | 2,900 | 39 | 22.0% |