| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 9°F | 29°F | 19°F | 1.3" |
| February | 11°F | 33°F | 22°F | 1.2" |
| March | 25°F | 49°F | 36°F | 1.9" |
| April | 36°F | 63°F | 49°F | 5.0" |
| May | 47°F | 74°F | 60°F | 4.8" |
| June | 58°F | 83°F | 71°F | 6.5" |
| July | 61°F | 86°F | 74°F | 4.9" |
| August | 58°F | 84°F | 71°F | 4.0" |
| September | 51°F | 79°F | 64°F | 3.4" |
| October | 39°F | 65°F | 51°F | 3.2" |
| November | 27°F | 50°F | 38°F | 1.8" |
| December | 14°F | 33°F | 23°F | 2.1" |
| Index | Denver | Iowa | National |
| Air quality index | 39 | 39 | 42 |
| Pollution index | 1,013,960 | 1,154,535 | 2,726,193 |
| Measurement | Total |
| Days measured | 363 |
| Days with good air quality | 286 |
| Days with moderate air quality | 77 |
| 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 | 0.001% |
| Lead | 0.001% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Waverly, IA | 10,172 | 39 | 22.0% |
| Jesup, IA | 2,725 | 39 | 22.0% |
| Evansdale, IA | 4,767 | 39 | 22.0% |
| Janesville, IA | 1,051 | 39 | 22.0% |
| Frederika, IA | 315 | 39 | 22.0% |
| Denver, IA | 1,759 | 39 | 22.0% |
| City | Population | Air Quality Index | National Avg. |
| Shelbina, MO | 1,759 | 41 | 18.0% |
| Weston, MO | 1,759 | 43 | 14.0% |
| Seneca Knolls, NY | 1,759 | 37 | 26.0% |
| Edgewood, TX | 1,759 | 36 | 28.0% |
| Preston, TX | 1,759 | 325 | 550.0% |
| Denver, IA | 1,759 | 39 | 22.0% |
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