| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 20°F | 38°F | 29°F | 2.4" |
| February | 20°F | 40°F | 30°F | 1.9" |
| March | 29°F | 51°F | 39°F | 2.6" |
| April | 39°F | 65°F | 52°F | 3.4" |
| May | 49°F | 75°F | 61°F | 3.8" |
| June | 59°F | 83°F | 71°F | 3.9" |
| July | 62°F | 86°F | 74°F | 4.7" |
| August | 60°F | 84°F | 71°F | 4.2" |
| September | 53°F | 78°F | 64°F | 4.4" |
| October | 43°F | 66°F | 53°F | 4.5" |
| November | 32°F | 54°F | 42°F | 3.0" |
| December | 26°F | 43°F | 34°F | 3.2" |
| Index | Millersburg | Pennsylvania | National |
| Air quality index | 44 | 45 | 42 |
| Pollution index | 11,091,200 | 4,584,805 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 252 |
| Days with moderate air quality | 107 |
| Days w/ poor A.Q. for sensitive groups | 5 |
| Days with unhealthy air quality | 1 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.140% |
| Carbon Tetrachloride | 0.030% |
| Lead | 0.310% |
| Mercury | 0.004% |
| City | Population | Air Quality Index | National Avg. |
| Beavertown, PA | 1,080 | 35 | 30.0% |
| Wiconsico, PA | 598 | 42 | 16.0% |
| Klingerstown, PA | 96 | 42 | 16.0% |
| Lykens, PA | 1,932 | 42 | 16.0% |
| Gratz, PA | 763 | 42 | 16.0% |
| Millersburg, PA | 2,514 | 44 | 12.0% |
| City | Population | Air Quality Index | National Avg. |
| Sumiton, AL | 2,514 | 53 | 6.0% |
| Waretown, NJ | 2,514 | 37 | 26.0% |
| Emsworth, PA | 2,514 | 56 | 12.0% |
| Calvert City, KY | 2,513 | 44 | 12.0% |
| Jonesville, NC | 2,513 | 45 | 10.0% |
| Millersburg, PA | 2,514 | 44 | 12.0% |
Here are the best places to live in Pennsylvania
Check out the 10 safest cities in Pennsylvania
Top 10 cities in Pennsylvania with the best education system
See the best places to live in & around Millersburg