| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 19°F | 34°F | 26°F | 2.6" |
| February | 19°F | 34°F | 26°F | 2.1" |
| March | 28°F | 46°F | 36°F | 2.9" |
| April | 39°F | 60°F | 48°F | 3.3" |
| May | 48°F | 68°F | 57°F | 4.5" |
| June | 57°F | 75°F | 66°F | 5.2" |
| July | 61°F | 79°F | 69°F | 4.5" |
| August | 59°F | 77°F | 68°F | 4.4" |
| September | 53°F | 71°F | 62°F | 4.1" |
| October | 43°F | 60°F | 51°F | 3.9" |
| November | 32°F | 49°F | 40°F | 2.6" |
| December | 24°F | 38°F | 31°F | 3.4" |
| Index | Indian Lake | Pennsylvania | National |
| Air quality index | 36 | 45 | 42 |
| Pollution index | 2,970,510 | 4,584,805 | 2,726,193 |
| Measurement | Total |
| Days measured | 359 |
| Days with good air quality | 340 |
| Days with moderate air quality | 19 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.050% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.650% |
| Mercury | 0.001% |
| City | Population | Air Quality Index | National Avg. |
| Edie, PA | 51 | 36 | 28.0% |
| Manns Choice, PA | 246 | 36 | 28.0% |
| Somerset, PA | 6,058 | 36 | 28.0% |
| Fairhope, PA | 1,190 | 36 | 28.0% |
| Jennerstown, PA | 1,215 | 36 | 28.0% |
| Indian Lake, PA | 397 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Nipinnawasee, CA | 397 | 50 | = 100 |
| Liscomb, IA | 397 | 37 | 26.0% |
| Carbon Hill, IL | 397 | 0 | 100.0% |
| Owensburg, IN | 397 | 42 | 16.0% |
| Midlothian, MD | 397 | 36 | 28.0% |
| Indian Lake, PA | 397 | 36 | 28.0% |