| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 23°F | 45°F | 33°F | 1.2" |
| February | 28°F | 53°F | 39°F | 2.6" |
| March | 35°F | 60°F | 46°F | 4.0" |
| April | 42°F | 72°F | 56°F | 3.9" |
| May | 49°F | 74°F | 61°F | 2.2" |
| June | 59°F | 85°F | 71°F | 6.7" |
| July | 63°F | 84°F | 73°F | 5.9" |
| August | 62°F | 85°F | 73°F | 5.3" |
| September | 56°F | 84°F | 68°F | 3.0" |
| October | 44°F | 72°F | 57°F | 5.5" |
| November | 33°F | 61°F | 46°F | 1.2" |
| December | 30°F | 51°F | 40°F | 3.4" |
| Index | Millfield | Ohio | National |
| Air quality index | 25 | 40 | 42 |
| Pollution index | 874,439 | 4,472,386 | 2,726,193 |
| Measurement | Total |
| Days measured | 120 |
| Days with good air quality | 116 |
| Days with moderate air quality | 4 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.010% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| New Straitsville, OH | 658 | 25 | 50.0% |
| Amesville, OH | 135 | 25 | 50.0% |
| Glouster, OH | 1,626 | 25 | 50.0% |
| Trimble, OH | 606 | 25 | 50.0% |
| Nelsonville, OH | 4,785 | 25 | 50.0% |
| Millfield, OH | 293 | 25 | 50.0% |
| City | Population | Air Quality Index | National Avg. |
| Harding-Birch Lakes, AK | 293 | 38 | 24.0% |
| Lower Kalskag, AK | 293 | 31 | 38.0% |
| Heath, AL | 293 | 35 | 30.0% |
| Elfrida, AZ | 293 | 45 | 10.0% |
| Clear Creek, CA | 293 | 46 | 8.0% |
| Millfield, OH | 293 | 25 | 50.0% |
Here are the best places to live in Ohio
10 best cities to buy a new house in Ohio
These are the 10 most affordable cities in Ohio
10 Best cities in Ohio for employment