| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 29°F | 44°F | 37°F | 11.4" |
| February | 31°F | 48°F | 40°F | 3.4" |
| March | 43°F | 62°F | 54°F | 4.4" |
| April | 49°F | 67°F | 59°F | 6.3" |
| May | 59°F | 79°F | 71°F | 6.6" |
| June | 66°F | 86°F | 78°F | 7.1" |
| July | 70°F | 89°F | 82°F | 6.4" |
| August | 72°F | 90°F | 83°F | 13.1" |
| September | 64°F | 82°F | 74°F | 18.6" |
| October | 51°F | 70°F | 61°F | 3.6" |
| November | 39°F | 60°F | 49°F | 7.5" |
| December | 28°F | 45°F | 36°F | 4.5" |
| Index | Salem | Missouri | National |
| Air quality index | 39 | 97 | 42 |
| Pollution index | 399,557 | 1,630,255 | 2,726,193 |
| Measurement | Total |
| Days measured | 245 |
| Days with good air quality | 238 |
| Days with moderate air quality | 7 |
| 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 | 0.002% |
| Lead | 0.001% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Salem, MO | 4,904 | 39 | 22.0% |
| City | Population | Air Quality Index | National Avg. |
| Margaret, AL | 4,905 | 53 | 6.0% |
| Winona Lake, IN | 4,902 | 31 | 38.0% |
| East Moriches, NY | 4,902 | 43 | 14.0% |
| Kneehill County, AB | 4,902 | n/a | |
| Pleasant Garden, NC | 4,906 | 43 | 14.0% |
| Salem, MO | 4,904 | 39 | 22.0% |
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