| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | -31°F | 61°F | 23°F | 0.4" |
| February | -15°F | 61°F | 24°F | 0.3" |
| March | 3°F | 79°F | 37°F | 1.4" |
| April | 19°F | 88°F | 50°F | 1.7" |
| May | 23°F | 91°F | 61°F | 2.4" |
| June | 46°F | 97°F | 71°F | 2.0" |
| July | 50°F | 100°F | 72°F | 2.3" |
| August | 46°F | 99°F | 71°F | 3.9" |
| September | 34°F | 91°F | 64°F | 1.4" |
| October | 21°F | 90°F | 51°F | 2.3" |
| November | 9°F | 73°F | 40°F | 1.1" |
| December | -13°F | 59°F | 24°F | 0.9" |
| Index | Charlotte | Iowa | National |
| Air quality index | 53 | 39 | 50 |
| Pollution index | 1,592,910 | 1,643,836 | 5,066,862 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 158 |
| Days with moderate air quality | 204 |
| Days w/ poor A.Q. for sensitive groups | 3 |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.090% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.010% |
| Mercury | 0.010% |
| City, State | Population | Air Quality Index | National Avg. |
| Camanche, IA | 4,368 | 53 | 6% |
| Goose Lake, IA | 275 | 53 | 6% |
| Miles, IA | 410 | 53 | 6% |
| Springbrook, IA | 137 | 53 | 6% |
| Andover, IA | 113 | 53 | 6% |
| Charlotte, IA | 404 | 53 | 6% |
| City, State | Population | Air Quality Index | National Avg. |
| Blandburg, PA | 404 | 45 | 10% |
| Island, KY | 404 | 40 | 20% |
| Rocky Mountain, OK | 404 | 36 | 28% |
| Ingold, NC | 404 | 37 | 26% |
| Orleans, NE | 404 | 19 | 62% |
| Charlotte, IA | 404 | 53 | 6% |