| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 25°F | 44°F | 33°F | 5.3" |
| February | 27°F | 47°F | 35°F | 4.6" |
| March | 37°F | 59°F | 47°F | 6.2" |
| April | 47°F | 69°F | 57°F | 9.5" |
| May | 55°F | 76°F | 65°F | 8.4" |
| June | 64°F | 86°F | 74°F | 6.1" |
| July | 67°F | 88°F | 77°F | 9.0" |
| August | 66°F | 87°F | 75°F | 9.8" |
| September | 58°F | 80°F | 68°F | 7.6" |
| October | 47°F | 69°F | 57°F | 7.0" |
| November | 37°F | 57°F | 46°F | 8.3" |
| December | 28°F | 45°F | 36°F | 4.6" |
| Index | Irondale | Missouri | National |
| Air quality index | 54 | 97 | 42 |
| Pollution index | 753,473 | 1,630,255 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 134 |
| Days with moderate air quality | 221 |
| Days w/ poor A.Q. for sensitive groups | 8 |
| Days with unhealthy air quality | 2 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.020% |
| Mercury | 0.020% |
| City | Population | Air Quality Index | National Avg. |
| Bismarck, MO | 1,731 | 54 | 8.0% |
| Doe Run, MO | 657 | 54 | 8.0% |
| Leadwood, MO | 1,579 | 54 | 8.0% |
| Wortham, MO | 429 | 54 | 8.0% |
| Iron Mountain Lake, MO | 705 | 54 | 8.0% |
| Irondale, MO | 575 | 54 | 8.0% |
| City | Population | Air Quality Index | National Avg. |
| Tolani Lake, AZ | 575 | 45 | 10.0% |
| Newton, GA | 575 | 40 | 20.0% |
| Minnesota Lake, MN | 575 | 15 | 70.0% |
| Kelso, MO | 575 | 44 | 12.0% |
| Wibaux, MT | 575 | 33 | 34.0% |
| Irondale, MO | 575 | 54 | 8.0% |
Here are the best places to live in Missouri
These are the 10 cheapest cities in Missouri
Check out the 10 most dangerous cities in Missouri
Most Dangerous Cities In The US