| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 15°F | 32°F | 23°F | 3.2" |
| February | 15°F | 33°F | 24°F | 3.6" |
| March | 23°F | 42°F | 32°F | 4.1" |
| April | 35°F | 57°F | 45°F | 4.2" |
| May | 47°F | 69°F | 57°F | 4.7" |
| June | 55°F | 75°F | 64°F | 6.5" |
| July | 61°F | 81°F | 71°F | 9.7" |
| August | 59°F | 79°F | 69°F | 7.2" |
| September | 53°F | 72°F | 62°F | 6.1" |
| October | 42°F | 60°F | 50°F | 8.4" |
| November | 31°F | 48°F | 39°F | 4.8" |
| December | 22°F | 36°F | 29°F | 3.9" |
| Index | Franklin | New Hampshire | National |
| Air quality index | 31 | 34 | 42 |
| Pollution index | 4,139,320 | 3,959,618 | 2,726,193 |
| Measurement | Total |
| Days measured | 316 |
| Days with good air quality | 308 |
| Days with moderate air quality | 8 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.060% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.020% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Bradford, NH | 306 | 27 | 46.0% |
| Warner, NH | 638 | 27 | 46.0% |
| Loudon, NH | 830 | 27 | 46.0% |
| Bristol, NH | 1,970 | 31 | 38.0% |
| New Hampton, NH | 326 | 31 | 38.0% |
| Franklin, NH | 8,695 | 31 | 38.0% |
| City | Population | Air Quality Index | National Avg. |
| Matawan, NJ | 8,696 | 51 | 2.0% |
| Castlegar, BC | 8,697 | n/a | |
| Sandpoint, ID | 8,692 | 43 | 14.0% |
| Iqaluit, NU | 8,699 | n/a | |
| Lake Norman of Catawba, NC | 8,701 | 36 | 28.0% |
| Franklin, NH | 8,695 | 31 | 38.0% |
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