| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 28°F | 46°F | 36°F | 5.4" |
| February | 30°F | 48°F | 38°F | 3.9" |
| March | 40°F | 60°F | 49°F | 7.8" |
| April | 49°F | 72°F | 60°F | 8.6" |
| May | 58°F | 79°F | 67°F | 6.3" |
| June | 67°F | 88°F | 77°F | 6.6" |
| July | 69°F | 88°F | 78°F | 6.4" |
| August | 67°F | 88°F | 77°F | 6.0" |
| September | 59°F | 82°F | 70°F | 5.5" |
| October | 48°F | 72°F | 59°F | 5.5" |
| November | 38°F | 59°F | 47°F | 5.8" |
| December | 32°F | 48°F | 39°F | 6.3" |
| Index | Marion | Kentucky | National |
| Air quality index | 44 | 45 | 42 |
| Pollution index | 768,150 | 1,369,131 | 2,726,193 |
| Measurement | Total |
| Days measured | 364 |
| Days with good air quality | 261 |
| Days with moderate air quality | 103 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.005% |
| Lead | 0.003% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Crayne, KY | 280 | 44 | 12.0% |
| Tolu, KY | 18 | 44 | 12.0% |
| Cave-In-Rock, IL | 199 | 44 | 12.0% |
| Dycusburg, KY | 62 | 44 | 12.0% |
| Elizabethtown, IL | 300 | 44 | 12.0% |
| Marion, KY | 2,885 | 44 | 12.0% |
| City | Population | Air Quality Index | National Avg. |
| Clinton, MI | 2,885 | 39 | 22.0% |
| Chincoteague, VA | 2,885 | 36 | 28.0% |
| Newton, IL | 2,884 | 40 | 20.0% |
| Cordaville, MA | 2,884 | 40 | 20.0% |
| Womelsdorf, PA | 2,886 | 42 | 16.0% |
| Marion, KY | 2,885 | 44 | 12.0% |
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