| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 17°F | 34°F | 25°F | 3.1" |
| February | 18°F | 36°F | 27°F | 2.2" |
| March | 28°F | 50°F | 38°F | 2.7" |
| April | 38°F | 64°F | 50°F | 3.6" |
| May | 48°F | 74°F | 61°F | 4.2" |
| June | 58°F | 83°F | 70°F | 4.2" |
| July | 62°F | 85°F | 73°F | 4.5" |
| August | 60°F | 83°F | 72°F | 4.9" |
| September | 53°F | 78°F | 65°F | 4.0" |
| October | 43°F | 65°F | 53°F | 4.5" |
| November | 32°F | 52°F | 41°F | 2.6" |
| December | 22°F | 38°F | 30°F | 2.8" |
| Index | Cassopolis | Michigan | National |
| Air quality index | 39 | 69 | 42 |
| Pollution index | 1,797,130 | 4,161,606 | 2,726,193 |
| Measurement | Total |
| Days measured | 260 |
| Days with good air quality | 232 |
| Days with moderate air quality | 26 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.002% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Bristol, IN | 1,539 | 37 | 26.0% |
| Simonton Lake, IN | 5,081 | 37 | 26.0% |
| Vandalia, MI | 387 | 37 | 26.0% |
| Marcellus, MI | 1,140 | 38 | 24.0% |
| Decatur, MI | 1,935 | 38 | 24.0% |
| Cassopolis, MI | 1,684 | 39 | 22.0% |
| City | Population | Air Quality Index | National Avg. |
| Rouse, CA | 1,684 | 49 | 2.0% |
| Knollwood, IL | 1,684 | 39 | 22.0% |
| Princeville, IL | 1,684 | 41 | 18.0% |
| East Helena, MT | 1,684 | 40 | 20.0% |
| Sturgeon Lake 154, AB | 1,684 | n/a | |
| Cassopolis, MI | 1,684 | 39 | 22.0% |
Here are the best places to live in Michigan
These are the 10 cheapest cities in Michigan
These are the largest cities in Michigan
See the best places to live in Cassopolis