| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 14°F | 33°F | 23°F | 4.0" |
| February | 14°F | 35°F | 24°F | 4.6" |
| March | 23°F | 44°F | 33°F | 6.9" |
| April | 34°F | 59°F | 46°F | 4.4" |
| May | 45°F | 70°F | 57°F | 5.3" |
| June | 54°F | 76°F | 65°F | 5.7" |
| July | 60°F | 82°F | 70°F | 10.6" |
| August | 57°F | 80°F | 67°F | 6.5" |
| September | 50°F | 73°F | 61°F | 8.8" |
| October | 40°F | 62°F | 49°F | 8.2" |
| November | 29°F | 49°F | 39°F | 4.3" |
| December | 21°F | 38°F | 29°F | 4.5" |
| Index | Marlborough | New Hampshire | National |
| Air quality index | 34 | 34 | 42 |
| Pollution index | 6,602,810 | 3,959,618 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 348 |
| Days with moderate air quality | 17 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.070% |
| Carbon Tetrachloride | 0.020% |
| Lead | 0.060% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Jaffrey, NH | 2,750 | 34 | 32.0% |
| Keene, NH | 22,823 | 34 | 32.0% |
| Winchester, NH | 1,939 | 34 | 32.0% |
| Antrim, NH | 1,364 | 34 | 32.0% |
| Peterborough, NH | 2,704 | 34 | 32.0% |
| Marlborough, NH | 1,093 | 34 | 32.0% |
| City | Population | Air Quality Index | National Avg. |
| Gales Ferry, CT | 1,093 | 37 | 26.0% |
| Bronson, FL | 1,093 | 35 | 30.0% |
| Hector, MN | 1,093 | 32 | 36.0% |
| Division No. 7, Subd. K, NL | 1,093 | n/a | |
| Pala, CA | 1,094 | 64 | 28.0% |
| Marlborough, NH | 1,093 | 34 | 32.0% |
Here are the best places to live in New Hampshire
These are the largest cities in New Hampshire
These are the 10 cheapest cities in New Hampshire
Safest Cities In The US