| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 17°F | 36°F | 26°F | 2.9" |
| February | 17°F | 38°F | 27°F | 2.5" |
| March | 27°F | 48°F | 36°F | 3.2" |
| April | 38°F | 65°F | 51°F | 4.6" |
| May | 47°F | 74°F | 61°F | 3.5" |
| June | 56°F | 82°F | 68°F | 7.2" |
| July | 59°F | 84°F | 71°F | 4.6" |
| August | 57°F | 84°F | 70°F | 5.3" |
| September | 52°F | 78°F | 64°F | 5.4" |
| October | 44°F | 68°F | 54°F | 4.5" |
| November | 31°F | 53°F | 41°F | 3.1" |
| December | 26°F | 44°F | 35°F | 4.0" |
| Index | Salem | Ohio | National |
| Air quality index | 42 | 40 | 42 |
| Pollution index | 2,559,460 | 4,472,386 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 276 |
| Days with moderate air quality | 89 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.005% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.030% |
| Lead | 0.060% |
| Mercury | 0.050% |
| City | Population | Air Quality Index | National Avg. |
| Lake Tomahawk, OH | 713 | 6 | 88.0% |
| Rogers, OH | 186 | 6 | 88.0% |
| Lisbon, OH | 2,671 | 6 | 88.0% |
| Hanoverton, OH | 310 | 6 | 88.0% |
| New Waterford, OH | 881 | 6 | 88.0% |
| Salem, OH | 11,692 | 42 | 16.0% |
| City | Population | Air Quality Index | National Avg. |
| Smyrna, DE | 11,694 | 42 | 16.0% |
| Tomball, TX | 11,689 | 52 | 4.0% |
| El Campo, TX | 11,695 | 31 | 38.0% |
| Excelsior Springs, MO | 11,688 | 47 | 6.0% |
| North Dumfries, ON | 11,684 | n/a | |
| Salem, OH | 11,692 | 42 | 16.0% |
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