| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 17°F | 37°F | 26°F | 1.8" |
| February | 19°F | 40°F | 29°F | 1.9" |
| March | 32°F | 55°F | 42°F | 3.1" |
| April | 42°F | 66°F | 53°F | 4.7" |
| May | 52°F | 74°F | 62°F | 4.8" |
| June | 62°F | 84°F | 72°F | 6.9" |
| July | 65°F | 87°F | 76°F | 4.3" |
| August | 63°F | 85°F | 73°F | 4.3" |
| September | 55°F | 79°F | 66°F | 4.1" |
| October | 44°F | 66°F | 54°F | 4.0" |
| November | 33°F | 54°F | 42°F | 2.6" |
| December | 22°F | 39°F | 30°F | 1.9" |
| Index | La Plata | Missouri | National |
| Air quality index | 41 | 97 | 42 |
| Pollution index | 637,848 | 1,630,255 | 2,726,193 |
| Measurement | Total |
| Days measured | 241 |
| Days with good air quality | 208 |
| Days with moderate air quality | 33 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.001% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Ethel, MO | 55 | 38 | 24.0% |
| Kirksville, MO | 18,120 | 41 | 18.0% |
| South Gifford, MO | 62 | 41 | 18.0% |
| Brashear, MO | 149 | 41 | 18.0% |
| Millard, MO | 75 | 41 | 18.0% |
| La Plata, MO | 1,231 | 41 | 18.0% |
| City | Population | Air Quality Index | National Avg. |
| Sycamore, GA | 1,231 | 40 | 20.0% |
| Lakeview, LA | 1,231 | 39 | 22.0% |
| Califon, NJ | 1,231 | 34 | 32.0% |
| Philadelphia, NY | 1,231 | 35 | 30.0% |
| Claysburg, PA | 1,231 | 41 | 18.0% |
| La Plata, MO | 1,231 | 41 | 18.0% |