| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 17°F | 33°F | 25°F | 2.3" |
| February | 18°F | 35°F | 26°F | 1.9" |
| March | 29°F | 49°F | 38°F | 2.2" |
| April | 39°F | 63°F | 50°F | 3.6" |
| May | 49°F | 73°F | 61°F | 4.2" |
| June | 59°F | 82°F | 71°F | 3.4" |
| July | 62°F | 84°F | 73°F | 4.1" |
| August | 60°F | 83°F | 71°F | 4.1" |
| September | 53°F | 77°F | 64°F | 3.2" |
| October | 43°F | 64°F | 53°F | 3.5" |
| November | 32°F | 51°F | 41°F | 2.7" |
| December | 23°F | 37°F | 30°F | 2.3" |
| Index | Simonton Lake | Indiana | National |
| Air quality index | 37 | 56 | 42 |
| Pollution index | 1,797,130 | 2,719,453 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 294 |
| Days with moderate air quality | 71 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| 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. |
| Dunlap, IN | 7,498 | 37 | 26.0% |
| Vandalia, MI | 403 | 37 | 26.0% |
| Elkhart, IN | 53,808 | 37 | 26.0% |
| Goshen, IN | 35,691 | 37 | 26.0% |
| Middlebury, IN | 3,663 | 37 | 26.0% |
| Simonton Lake, IN | 5,279 | 37 | 26.0% |
| City | Population | Air Quality Index | National Avg. |
| La Crescent, MN | 5,277 | 35 | 30.0% |
| Savannah, MO | 5,277 | 43 | 14.0% |
| Flanders, NY | 5,277 | 41 | 18.0% |
| Perry, UT | 5,277 | 44 | 12.0% |
| Beckett, NJ | 5,281 | 51 | 2.0% |
| Simonton Lake, IN | 5,279 | 37 | 26.0% |