| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 29°F | 43°F | 35°F | 7.5" |
| February | 26°F | 42°F | 33°F | 4.8" |
| March | 38°F | 58°F | 48°F | 4.2" |
| April | 45°F | 67°F | 55°F | 4.7" |
| May | 55°F | 79°F | 67°F | 5.3" |
| June | 65°F | 88°F | 76°F | 6.9" |
| July | 67°F | 88°F | 77°F | 8.1" |
| August | 70°F | 92°F | 80°F | 7.5" |
| September | 61°F | 86°F | 72°F | 4.9" |
| October | 50°F | 73°F | 60°F | 5.1" |
| November | 36°F | 58°F | 46°F | 9.7" |
| December | 27°F | 42°F | 34°F | 4.3" |
| Index | Russellville | Illinois | National |
| Air quality index | 36 | 41 | 42 |
| Pollution index | 1,453,840 | 3,148,694 | 2,726,193 |
| Measurement | Total |
| Days measured | 359 |
| Days with good air quality | 328 |
| Days with moderate air quality | 31 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.004% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Ragsdale, IN | 248 | 1 | 98.0% |
| Freelandville, IN | 759 | 1 | 98.0% |
| Wheatland, IN | 450 | 1 | 98.0% |
| Bicknell, IN | 2,715 | 1 | 98.0% |
| Emison, IN | 78 | 36 | 28.0% |
| Russellville, IL | 75 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| False Pass, AK | 75 | 31 | 38.0% |
| Lowndesboro, AL | 75 | 52 | 4.0% |
| Omaha, AR | 75 | 18 | 64.0% |
| Franklin, AZ | 75 | 37 | 26.0% |
| Gold Mountain, CA | 75 | 44 | 12.0% |
| Russellville, IL | 75 | 36 | 28.0% |
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