| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 20°F | 33°F | 26°F | 3.6" |
| February | 18°F | 32°F | 24°F | 3.0" |
| March | 30°F | 49°F | 39°F | 3.1" |
| April | 39°F | 62°F | 49°F | 5.2" |
| May | 49°F | 72°F | 60°F | 3.7" |
| June | 60°F | 83°F | 72°F | 4.9" |
| July | 62°F | 84°F | 73°F | 7.8" |
| August | 64°F | 84°F | 74°F | 8.3" |
| September | 56°F | 80°F | 68°F | 2.9" |
| October | 47°F | 67°F | 56°F | 4.3" |
| November | 32°F | 50°F | 40°F | 3.1" |
| December | 18°F | 32°F | 25°F | 2.2" |
| Index | West Chicago | Illinois | National |
| Air quality index | 60 | 41 | 50 |
| Pollution index | 14,981,300 | 3,347,295 | 5,066,862 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 72 |
| Days with moderate air quality | 281 |
| Days w/ poor A.Q. for sensitive groups | 11 |
| Days with unhealthy air quality | 1 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.140% |
| Carbon Tetrachloride | 0.030% |
| Lead | 0.020% |
| Mercury | 0.010% |
| City, State | Population | Air Quality Index | National Avg. |
| Sugar Grove, IL | 9,288 | 1 | 98% |
| Oswego, IL | 33,245 | 1 | 98% |
| Montgomery, IL | 19,055 | 1 | 98% |
| Prestbury, IL | 1,780 | 1 | 98% |
| Lily Lake, IL | 1,253 | 31 | 38% |
| West Chicago, IL | 27,420 | 60 | 20% |
| City, State | Population | Air Quality Index | National Avg. |
| Cornelius, NC | 27,426 | 42 | 16% |
| Lake Jackson, TX | 27,407 | 52 | 4% |
| Dix Hills, NY | 27,403 | 47 | 6% |
| Reisterstown, MD | 27,401 | 46 | 8% |
| Jeffersontown, KY | 27,395 | 55 | 10% |
| West Chicago, IL | 27,420 | 60 | 20% |