| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 19°F | 38°F | 28°F | 2.6" |
| February | 19°F | 40°F | 29°F | 2.6" |
| March | 28°F | 50°F | 38°F | 3.1" |
| April | 38°F | 64°F | 51°F | 3.3" |
| May | 48°F | 74°F | 60°F | 3.1" |
| June | 57°F | 80°F | 68°F | 5.7" |
| July | 62°F | 85°F | 73°F | 5.0" |
| August | 59°F | 82°F | 70°F | 5.4" |
| September | 52°F | 76°F | 63°F | 4.6" |
| October | 42°F | 66°F | 53°F | 4.4" |
| November | 32°F | 53°F | 42°F | 2.5" |
| December | 25°F | 43°F | 33°F | 3.8" |
| Index | Franklin | New Jersey | National |
| Air quality index | 34 | 45 | 42 |
| Pollution index | 3,291,140 | 7,246,891 | 2,726,193 |
| Measurement | Total |
| Days measured | 349 |
| Days with good air quality | 340 |
| Days with moderate air quality | 9 |
| 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 | 0.020% |
| Mercury | 0.001% |
| City | Population | Air Quality Index | National Avg. |
| Andover, NJ | 675 | 34 | 32.0% |
| Mount Arlington, NJ | 5,751 | 34 | 32.0% |
| Wharton, NJ | 6,458 | 34 | 32.0% |
| Branchville, NJ | 1,054 | 34 | 32.0% |
| Newton, NJ | 7,935 | 34 | 32.0% |
| Franklin, NJ | 4,737 | 34 | 32.0% |
| City | Population | Air Quality Index | National Avg. |
| Hillandale, MD | 4,737 | 47 | 6.0% |
| Dundee, FL | 4,738 | 36 | 28.0% |
| Morganville, NJ | 4,738 | 41 | 18.0% |
| Harrington Park, NJ | 4,735 | 51 | 2.0% |
| Blue Point, NY | 4,739 | 43 | 14.0% |
| Franklin, NJ | 4,737 | 34 | 32.0% |
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