| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 24°F | 41°F | 31°F | 3.4" |
| February | 25°F | 43°F | 33°F | 3.7" |
| March | 38°F | 57°F | 46°F | 3.1" |
| April | 47°F | 68°F | 56°F | 6.6" |
| May | 56°F | 76°F | 65°F | 6.1" |
| June | 65°F | 85°F | 75°F | 3.5" |
| July | 67°F | 87°F | 77°F | 7.3" |
| August | 66°F | 86°F | 75°F | 6.8" |
| September | 58°F | 80°F | 68°F | 4.4" |
| October | 47°F | 68°F | 57°F | 6.7" |
| November | 36°F | 56°F | 45°F | 4.9" |
| December | 28°F | 43°F | 35°F | 6.3" |
| Index | Godfrey | Illinois | National |
| Air quality index | 54 | 41 | 42 |
| Pollution index | 8,870,230 | 3,148,694 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 134 |
| Days with moderate air quality | 221 |
| Days w/ poor A.Q. for sensitive groups | 8 |
| Days with unhealthy air quality | 2 |
| Pollutant | Total |
| Arsenic | 0.180% |
| Benzene | 0.060% |
| Carbon Tetrachloride | 0.020% |
| Lead | 0.030% |
| Mercury | 0.120% |
| City | Population | Air Quality Index | National Avg. |
| Jerseyville, IL | 7,860 | 54 | 8.0% |
| Bunker Hill, IL | 1,468 | 54 | 8.0% |
| Black Jack, MO | 6,930 | 54 | 8.0% |
| Bethalto, IL | 9,258 | 54 | 8.0% |
| Hartford, IL | 1,769 | 54 | 8.0% |
| Godfrey, IL | 17,540 | 54 | 8.0% |
| City | Population | Air Quality Index | National Avg. |
| Marion, IL | 17,539 | 43 | 14.0% |
| Lithia Springs, GA | 17,545 | 52 | 4.0% |
| Bostonia, CA | 17,532 | 64 | 28.0% |
| Wantagh, NY | 17,548 | 51 | 2.0% |
| Manassas Park, VA | 17,548 | 47 | 6.0% |
| Godfrey, IL | 17,540 | 54 | 8.0% |
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