| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 16°F | 32°F | 23°F | 4.0" |
| February | 14°F | 33°F | 24°F | 3.9" |
| March | 22°F | 43°F | 32°F | 5.4" |
| April | 35°F | 55°F | 45°F | 13.1" |
| May | 44°F | 66°F | 54°F | 8.4" |
| June | 54°F | 78°F | 66°F | 4.0" |
| July | 59°F | 82°F | 70°F | 4.3" |
| August | 58°F | 83°F | 70°F | 4.0" |
| September | 52°F | 76°F | 63°F | 3.7" |
| October | 44°F | 62°F | 53°F | 13.0" |
| November | 31°F | 49°F | 39°F | 7.8" |
| December | 19°F | 35°F | 27°F | 4.5" |
| Index | Rochester | New Hampshire | National |
| Air quality index | 27 | 34 | 42 |
| Pollution index | 91,790 | 3,959,618 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 360 |
| Days with moderate air quality | 5 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.002% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.001% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Berwick, ME | 1,985 | 27 | 46.0% |
| Alton, NH | 170 | 31 | 38.0% |
| Milton Mills, NH | 216 | 31 | 38.0% |
| Farmington, NH | 4,140 | 31 | 38.0% |
| Union, NH | 242 | 31 | 38.0% |
| Rochester, NH | 31,305 | 27 | 46.0% |
| City | Population | Air Quality Index | National Avg. |
| Grimsby, ON | 31,320 | n/a | |
| Saratoga Springs, UT | 31,273 | 46 | 8.0% |
| West Falls Church, VA | 31,262 | 47 | 6.0% |
| Orcutt, CA | 31,353 | 46 | 8.0% |
| Redmond, OR | 31,359 | 20 | 60.0% |
| Rochester, NH | 31,305 | 27 | 46.0% |
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