| 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 | Mercer | Pennsylvania | National |
| Air quality index | 31 | 45 | 42 |
| Pollution index | 601,986 | 4,584,805 | 2,726,193 |
| Measurement | Total |
| Days measured | 361 |
| Days with good air quality | 356 |
| Days with moderate air quality | 5 |
| 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 | 0.010% |
| Mercury | 0.001% |
| City | Population | Air Quality Index | National Avg. |
| New Castle Northwest, PA | 1,235 | 31 | 38.0% |
| Barkeyville, PA | 287 | 31 | 38.0% |
| New Wilmington, PA | 2,196 | 31 | 38.0% |
| Sandy Lake, PA | 777 | 31 | 38.0% |
| New Lebanon, PA | 202 | 31 | 38.0% |
| Mercer, PA | 1,755 | 31 | 38.0% |
| City | Population | Air Quality Index | National Avg. |
| Kaibito, AZ | 1,755 | 45 | 10.0% |
| Portola, CA | 1,755 | 44 | 12.0% |
| Prudenville, MI | 1,755 | 36 | 28.0% |
| Decatur, MS | 1,755 | 36 | 28.0% |
| Corvallis, MT | 1,755 | 40 | 20.0% |
| Mercer, PA | 1,755 | 31 | 38.0% |
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