| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 20°F | 38°F | 28°F | 3.1" |
| February | 19°F | 40°F | 29°F | 2.4" |
| March | 28°F | 52°F | 39°F | 3.1" |
| April | 38°F | 66°F | 51°F | 3.8" |
| May | 48°F | 75°F | 61°F | 3.9" |
| June | 58°F | 83°F | 70°F | 4.1" |
| July | 62°F | 87°F | 74°F | 4.7" |
| August | 60°F | 84°F | 71°F | 5.3" |
| September | 54°F | 79°F | 65°F | 4.3" |
| October | 43°F | 66°F | 53°F | 4.9" |
| November | 32°F | 54°F | 42°F | 3.0" |
| December | 26°F | 43°F | 34°F | 4.0" |
| Index | Williamsport | Pennsylvania | National |
| Air quality index | 35 | 45 | 42 |
| Pollution index | 1,515,200 | 4,584,805 | 2,726,193 |
| Measurement | Total |
| Days measured | 361 |
| Days with good air quality | 340 |
| Days with moderate air quality | 21 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.050% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.020% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Loganton, PA | 481 | 35 | 30.0% |
| Montgomery, PA | 1,494 | 35 | 30.0% |
| Kenmar, PA | 3,895 | 35 | 30.0% |
| Oval, PA | 410 | 35 | 30.0% |
| McEwensville, PA | 338 | 35 | 30.0% |
| Williamsport, PA | 28,437 | 35 | 30.0% |
| City | Population | Air Quality Index | National Avg. |
| Woolwich, ON | 28,438 | n/a | |
| Jacksonville, AR | 28,442 | 45 | 10.0% |
| Burbank, IL | 28,447 | 55 | 10.0% |
| Temescal Valley, CA | 28,420 | 89 | 78.0% |
| Henderson, KY | 28,469 | 45 | 10.0% |
| Williamsport, PA | 28,437 | 35 | 30.0% |
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