| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 20°F | 38°F | 28°F | 3.4" |
| February | 20°F | 40°F | 30°F | 2.3" |
| March | 31°F | 53°F | 41°F | 4.0" |
| April | 41°F | 67°F | 53°F | 4.5" |
| May | 51°F | 75°F | 63°F | 4.1" |
| June | 61°F | 84°F | 72°F | 4.5" |
| July | 63°F | 85°F | 74°F | 4.3" |
| August | 62°F | 85°F | 73°F | 2.9" |
| September | 55°F | 79°F | 67°F | 4.3" |
| October | 44°F | 67°F | 55°F | 3.5" |
| November | 33°F | 55°F | 43°F | 3.1" |
| December | 25°F | 42°F | 33°F | 3.9" |
| Index | Sidney | Ohio | National |
| Air quality index | 39 | 40 | 42 |
| Pollution index | 1,662,340 | 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 | 0.003% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.003% |
| Lead | 0.030% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| New Bremen, OH | 2,857 | 39 | 22.0% |
| Kettlersville, OH | 137 | 39 | 22.0% |
| Port Jefferson, OH | 447 | 39 | 22.0% |
| Anna, OH | 1,655 | 39 | 22.0% |
| Lakeview, OH | 1,171 | 39 | 22.0% |
| Sidney, OH | 21,359 | 39 | 22.0% |
| City | Population | Air Quality Index | National Avg. |
| East Moline, IL | 21,358 | 46 | 8.0% |
| Dickinson, TX | 21,358 | 52 | 4.0% |
| South El Monte, CA | 21,353 | 72 | 44.0% |
| Lebanon, OH | 21,351 | 43 | 14.0% |
| Marquette, MI | 21,369 | 8 | 84.0% |
| Sidney, OH | 21,359 | 39 | 22.0% |