| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 22°F | 36°F | 28°F | 5.9" |
| February | 16°F | 31°F | 23°F | 2.8" |
| March | 29°F | 49°F | 38°F | 2.2" |
| April | 38°F | 61°F | 49°F | 5.4" |
| May | 47°F | 74°F | 60°F | 3.5" |
| June | 60°F | 85°F | 72°F | 3.2" |
| July | 61°F | 85°F | 73°F | 7.1" |
| August | 62°F | 84°F | 73°F | 12.6" |
| September | 53°F | 80°F | 66°F | 4.9" |
| October | 47°F | 67°F | 56°F | 3.6" |
| November | 31°F | 52°F | 41°F | 6.4" |
| December | 21°F | 33°F | 27°F | 4.1" |
| Index | Waterloo | Indiana | National |
| Air quality index | 45 | 56 | 42 |
| Pollution index | 2,775,870 | 2,719,453 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 236 |
| Days with moderate air quality | 128 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.380% |
| Mercury | 0.030% |
| City | Population | Air Quality Index | National Avg. |
| Garrett, IN | 6,507 | 45 | 10.0% |
| Leo-Cedarville, IN | 3,814 | 45 | 10.0% |
| Altona, IN | 509 | 45 | 10.0% |
| Edgerton, OH | 2,175 | 45 | 10.0% |
| Ashley, IN | 1,051 | 45 | 10.0% |
| Waterloo, IN | 2,217 | 45 | 10.0% |
| City | Population | Air Quality Index | National Avg. |
| Davisboro, GA | 2,217 | 47 | 6.0% |
| Eureka, KS | 2,217 | 22 | 56.0% |
| Hide-A-Way Lake, MS | 2,217 | 42 | 16.0% |
| Pulaski, NY | 2,217 | 35 | 30.0% |
| Riverside, PA | 2,217 | 35 | 30.0% |
| Waterloo, IN | 2,217 | 45 | 10.0% |
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