| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 17°F | 35°F | 25°F | 1.1" |
| February | 20°F | 38°F | 28°F | 1.5" |
| March | 33°F | 53°F | 41°F | 1.9" |
| April | 43°F | 65°F | 53°F | 3.7" |
| May | 53°F | 75°F | 64°F | 5.1" |
| June | 63°F | 84°F | 73°F | 5.5" |
| July | 66°F | 87°F | 76°F | 4.1" |
| August | 64°F | 84°F | 74°F | 3.3" |
| September | 56°F | 79°F | 67°F | 3.3" |
| October | 45°F | 68°F | 55°F | 3.0" |
| November | 33°F | 53°F | 42°F | 2.4" |
| December | 23°F | 39°F | 31°F | 1.9" |
| Index | Elvaston | Illinois | National |
| Air quality index | 29 | 41 | 42 |
| Pollution index | 802,114 | 3,148,694 | 2,726,193 |
| Measurement | Total |
| Days measured | 120 |
| Days with good air quality | 101 |
| Days with moderate air quality | 19 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.040% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Montrose, IA | 844 | 29 | 42.0% |
| Hamilton, IL | 2,808 | 29 | 42.0% |
| Alexandria, MO | 105 | 29 | 42.0% |
| Basco, IL | 85 | 29 | 42.0% |
| Nauvoo, IL | 948 | 29 | 42.0% |
| Elvaston, IL | 151 | 29 | 42.0% |
| City | Population | Air Quality Index | National Avg. |
| Kobuk, AK | 151 | 38 | 24.0% |
| Cutter, AZ | 151 | 60 | 20.0% |
| North San Juan, CA | 151 | 44 | 12.0% |
| Winterhaven, CA | 151 | 45 | 10.0% |
| Montezuma, CO | 151 | 47 | 6.0% |
| Elvaston, IL | 151 | 29 | 42.0% |
Here are the best places to live in Illinois
These are the 10 most affordable cities in Illinois
10 Best cities in Illinois for employment
Check out the 10 safest cities in Illinois