| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 24°F | 39°F | 31°F | 2.9" |
| February | 26°F | 42°F | 33°F | 2.8" |
| March | 34°F | 53°F | 43°F | 4.1" |
| April | 44°F | 65°F | 54°F | 4.9" |
| May | 53°F | 73°F | 63°F | 4.8" |
| June | 62°F | 82°F | 71°F | 5.4" |
| July | 66°F | 86°F | 76°F | 4.0" |
| August | 64°F | 84°F | 73°F | 4.2" |
| September | 58°F | 77°F | 67°F | 5.2" |
| October | 48°F | 67°F | 57°F | 5.8" |
| November | 38°F | 55°F | 46°F | 3.1" |
| December | 31°F | 45°F | 38°F | 4.6" |
| Index | Orrstown | Pennsylvania | National |
| Air quality index | 36 | 45 | 42 |
| Pollution index | 1,656,460 | 4,584,805 | 2,726,193 |
| Measurement | Total |
| Days measured | 341 |
| Days with good air quality | 324 |
| Days with moderate air quality | 17 |
| 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 | 0.002% |
| Lead | 0.004% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Shippensburg University, PA | 1,948 | 36 | 28.0% |
| Marion, PA | 1,596 | 36 | 28.0% |
| Guilford, PA | 3,698 | 36 | 28.0% |
| Shade Gap, PA | 128 | 36 | 28.0% |
| Scotland, PA | 763 | 36 | 28.0% |
| Orrstown, PA | 350 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Edmundson Acres, CA | 350 | 67 | 34.0% |
| Mexican Colony, CA | 350 | 67 | 34.0% |
| Princeton, CA | 350 | 46 | 8.0% |
| Boyne Falls, MI | 350 | 36 | 28.0% |
| Beaver Creek, MN | 350 | 36 | 28.0% |
| Orrstown, PA | 350 | 36 | 28.0% |