| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 17°F | 33°F | 25°F | 2.2" |
| February | 17°F | 34°F | 25°F | 1.8" |
| March | 27°F | 47°F | 36°F | 2.2" |
| April | 37°F | 61°F | 48°F | 3.3" |
| May | 47°F | 72°F | 59°F | 3.8" |
| June | 57°F | 80°F | 69°F | 4.0" |
| July | 60°F | 83°F | 72°F | 3.7" |
| August | 59°F | 81°F | 70°F | 4.2" |
| September | 52°F | 75°F | 63°F | 3.0" |
| October | 42°F | 63°F | 52°F | 3.1" |
| November | 32°F | 50°F | 40°F | 2.3" |
| December | 23°F | 37°F | 30°F | 2.0" |
| Index | Napoleon | Michigan | National |
| Air quality index | 39 | 69 | 42 |
| Pollution index | 3,811,680 | 4,161,606 | 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 | 0.004% |
| Benzene | 0.040% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.040% |
| Mercury | 0.002% |
| City | Population | Air Quality Index | National Avg. |
| Michigan Center, MI | 4,879 | 39 | 22.0% |
| Addison, MI | 633 | 39 | 22.0% |
| Cement City, MI | 520 | 39 | 22.0% |
| Vandercook Lake, MI | 4,702 | 39 | 22.0% |
| Manitou Beach-Devils Lake, MI | 1,923 | 39 | 22.0% |
| Napoleon, MI | 905 | 39 | 22.0% |
| City | Population | Air Quality Index | National Avg. |
| Ganado, AZ | 905 | 17 | 66.0% |
| Boyden, IA | 905 | 36 | 28.0% |
| Bird Island, MN | 905 | 32 | 36.0% |
| Kindred, ND | 905 | 33 | 34.0% |
| Genoa, NE | 905 | 19 | 62.0% |
| Napoleon, MI | 905 | 39 | 22.0% |
Here are the best places to live in Michigan
Check out the 10 most dangerous cities in Michigan
These are the 10 cheapest cities in Michigan
Most Dangerous Cities In The US