| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 16°F | 33°F | 24°F | 0.5" |
| February | 18°F | 36°F | 26°F | 1.3" |
| March | 31°F | 52°F | 40°F | 7.8" |
| April | 41°F | 65°F | 52°F | 9.4" |
| May | 52°F | 74°F | 62°F | 8.4" |
| June | 62°F | 84°F | 72°F | 5.7" |
| July | 65°F | 87°F | 76°F | 6.6" |
| August | 63°F | 84°F | 73°F | 4.1" |
| September | 55°F | 79°F | 66°F | 7.3" |
| October | 43°F | 66°F | 54°F | 4.3" |
| November | 32°F | 52°F | 41°F | 2.7" |
| December | 20°F | 37°F | 28°F | 3.3" |
| Index | Monroe | Iowa | National |
| Air quality index | 39 | 39 | 50 |
| Pollution index | 3,955,060 | 1,643,836 | 5,066,862 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 306 |
| Days with moderate air quality | 59 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.002% |
| Mercury | 0.000% |
| City, State | Population | Air Quality Index | National Avg. |
| Knoxville, IA | 7,236 | 39 | 22% |
| Sully, IA | 843 | 39 | 22% |
| Sandyville, IA | 74 | 39 | 22% |
| Colfax, IA | 1,925 | 39 | 22% |
| Valeria, IA | 46 | 39 | 22% |
| Monroe, IA | 1,875 | 39 | 22% |
| City, State | Population | Air Quality Index | National Avg. |
| Dakota City, NE | 1,875 | 35 | 30% |
| New Union, TN | 1,875 | 25 | 50% |
| Leadville North, CO | 1,875 | 47 | 6% |
| Moweaqua, IL | 1,874 | 44 | 12% |
| Lake Hamilton, AR | 1,874 | 38 | 24% |
| Monroe, IA | 1,875 | 39 | 22% |
Here are the best places to live in Iowa
10 best cities to buy a new house in Iowa
Top 10 best public schools in Monroe
These are the 10 most affordable cities in Iowa