| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 21°F | 44°F | 31°F | 2.0" |
| February | 23°F | 47°F | 33°F | 2.1" |
| March | 35°F | 61°F | 46°F | 3.0" |
| April | 44°F | 71°F | 57°F | 5.7" |
| May | 53°F | 78°F | 65°F | 4.3" |
| June | 63°F | 87°F | 75°F | 4.8" |
| July | 67°F | 90°F | 78°F | 5.1" |
| August | 65°F | 89°F | 76°F | 3.9" |
| September | 57°F | 82°F | 69°F | 4.8" |
| October | 45°F | 71°F | 57°F | 3.9" |
| November | 35°F | 59°F | 46°F | 2.4" |
| December | 25°F | 45°F | 34°F | 2.7" |
| Index | Montgomery City | Missouri | National |
| Air quality index | 38 | 97 | 42 |
| Pollution index | 732,008 | 1,630,255 | 2,726,193 |
| Measurement | Total |
| Days measured | 245 |
| Days with good air quality | 239 |
| Days with moderate air quality | 6 |
| 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 | 0.001% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Middletown, MO | 222 | 38 | 24.0% |
| Wellsville, MO | 1,176 | 38 | 24.0% |
| Bellflower, MO | 348 | 38 | 24.0% |
| Benton City, MO | 144 | 38 | 24.0% |
| Truxton, MO | 149 | 38 | 24.0% |
| Montgomery City, MO | 2,765 | 38 | 24.0% |
| City | Population | Air Quality Index | National Avg. |
| Channel Islands Beach, CA | 2,765 | 46 | 8.0% |
| Lucerne, CA | 2,765 | 31 | 38.0% |
| Bells, TN | 2,765 | 27 | 46.0% |
| New Town, ND | 2,764 | 34 | 32.0% |
| Kulpmont, PA | 2,764 | 42 | 16.0% |
| Montgomery City, MO | 2,765 | 38 | 24.0% |