| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 21°F | 37°F | 28°F | 2.0" |
| February | 21°F | 38°F | 29°F | 1.6" |
| March | 29°F | 49°F | 39°F | 2.9" |
| April | 40°F | 63°F | 51°F | 3.1" |
| May | 49°F | 72°F | 60°F | 4.2" |
| June | 58°F | 79°F | 68°F | 4.2" |
| July | 61°F | 83°F | 72°F | 4.1" |
| August | 59°F | 81°F | 69°F | 3.6" |
| September | 53°F | 75°F | 63°F | 3.3" |
| October | 44°F | 64°F | 53°F | 3.6" |
| November | 33°F | 52°F | 42°F | 2.2" |
| December | 26°F | 41°F | 33°F | 3.1" |
| Index | Shirleysburg | 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. |
| East Waterford, PA | 174 | 36 | 28.0% |
| Rockhill, PA | 348 | 36 | 28.0% |
| Saltillo, PA | 355 | 36 | 28.0% |
| Shade Gap, PA | 124 | 36 | 28.0% |
| Orbisonia, PA | 449 | 36 | 28.0% |
| Shirleysburg, PA | 161 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Flournoy, CA | 161 | 41 | 18.0% |
| Hasty, CO | 161 | 20 | 60.0% |
| Pilot Mound, IA | 161 | 37 | 26.0% |
| Rock Falls, IA | 161 | 15 | 70.0% |
| Westphalia, IA | 161 | 40 | 20.0% |
| Shirleysburg, PA | 161 | 36 | 28.0% |
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