| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 18°F | 35°F | 26°F | 1.8" |
| February | 19°F | 37°F | 27°F | 1.7" |
| March | 34°F | 53°F | 42°F | 3.5" |
| April | 45°F | 66°F | 55°F | 5.3" |
| May | 54°F | 75°F | 64°F | 4.8" |
| June | 64°F | 84°F | 74°F | 6.7" |
| July | 67°F | 86°F | 76°F | 5.2" |
| August | 66°F | 85°F | 75°F | 6.2" |
| September | 58°F | 80°F | 68°F | 3.5" |
| October | 46°F | 65°F | 55°F | 3.9" |
| November | 37°F | 54°F | 45°F | 2.2" |
| December | 22°F | 37°F | 29°F | 3.1" |
| Index | Keithsburg | Illinois | National |
| Air quality index | 32 | 41 | 42 |
| Pollution index | 640,499 | 3,148,694 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 300 |
| Days with moderate air quality | 65 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.003% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Mediapolis, IA | 2,118 | 29 | 42.0% |
| Oquawka, IL | 1,352 | 29 | 42.0% |
| Aledo, IL | 3,625 | 32 | 36.0% |
| Seaton, IL | 278 | 32 | 36.0% |
| Joy, IL | 292 | 32 | 36.0% |
| Keithsburg, IL | 524 | 32 | 36.0% |
| City | Population | Air Quality Index | National Avg. |
| Orleans, IA | 524 | 32 | 36.0% |
| Washburn, IA | 524 | 39 | 22.0% |
| Patriot, IN | 524 | 54 | 8.0% |
| Richmond, KS | 524 | 41 | 18.0% |
| Cosmos, MN | 524 | 32 | 36.0% |
| Keithsburg, IL | 524 | 32 | 36.0% |
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