| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 23°F | 41°F | 32°F | 2.9" |
| February | 23°F | 42°F | 32°F | 2.8" |
| March | 32°F | 53°F | 42°F | 3.4" |
| April | 42°F | 66°F | 53°F | 4.0" |
| May | 51°F | 75°F | 63°F | 4.0" |
| June | 61°F | 82°F | 71°F | 4.7" |
| July | 66°F | 87°F | 76°F | 4.9" |
| August | 63°F | 84°F | 73°F | 5.2" |
| September | 56°F | 78°F | 67°F | 4.7" |
| October | 45°F | 67°F | 56°F | 4.5" |
| November | 35°F | 55°F | 45°F | 2.6" |
| December | 29°F | 46°F | 37°F | 4.2" |
| Index | Bally | Pennsylvania | National |
| Air quality index | 42 | 45 | 42 |
| Pollution index | 8,206,310 | 4,584,805 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 275 |
| Days with moderate air quality | 86 |
| Days w/ poor A.Q. for sensitive groups | 4 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.260% |
| Benzene | 0.060% |
| Carbon Tetrachloride | 0.020% |
| Lead | 0.160% |
| Mercury | 1.120% |
| City | Population | Air Quality Index | National Avg. |
| Sellersville, PA | 4,279 | 42 | 16.0% |
| Allentown, PA | 121,156 | 42 | 16.0% |
| Hellertown, PA | 5,835 | 42 | 16.0% |
| Bowers, PA | 247 | 42 | 16.0% |
| Kutztown University, PA | 3,898 | 42 | 16.0% |
| Bally, PA | 1,300 | 42 | 16.0% |
| City | Population | Air Quality Index | National Avg. |
| Hamburg, IA | 1,300 | 40 | 20.0% |
| Albany, LA | 1,300 | 30 | 40.0% |
| Eastport, ME | 1,300 | 31 | 38.0% |
| Barneveld, WI | 1,300 | 39 | 22.0% |
| Fortune, NL | 1,300 | n/a | |
| Bally, PA | 1,300 | 42 | 16.0% |
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