| 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 | Pontoosuc | 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. |
| West Point, IA | 735 | 29 | 42.0% |
| Carthage, IL | 2,474 | 29 | 42.0% |
| Gulf Port, IL | 21 | 29 | 42.0% |
| Burlington, IA | 24,858 | 29 | 42.0% |
| Denmark, IA | 504 | 29 | 42.0% |
| Pontoosuc, IL | 109 | 29 | 42.0% |
| City | Population | Air Quality Index | National Avg. |
| Eagle, AK | 109 | 38 | 24.0% |
| Mud Bay, AK | 109 | 20 | 60.0% |
| Standing Rock, AL | 109 | 42 | 16.0% |
| Kohls Ranch, AZ | 109 | 60 | 20.0% |
| Vilas, CO | 109 | 20 | 60.0% |
| Pontoosuc, IL | 109 | 29 | 42.0% |
Here are the best places to live in Illinois
Safest States In The US
These are the 10 cheapest cities in Illinois
These are the largest cities in Illinois