| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 10°F | 31°F | 21°F | 2.4" |
| February | 10°F | 32°F | 21°F | 2.2" |
| March | 19°F | 41°F | 30°F | 2.4" |
| April | 32°F | 55°F | 43°F | 3.3" |
| May | 44°F | 68°F | 55°F | 4.0" |
| June | 52°F | 75°F | 63°F | 4.8" |
| July | 58°F | 82°F | 70°F | 2.7" |
| August | 57°F | 81°F | 68°F | 3.7" |
| September | 50°F | 74°F | 61°F | 3.9" |
| October | 40°F | 61°F | 50°F | 5.5" |
| November | 28°F | 48°F | 38°F | 3.1" |
| December | 17°F | 35°F | 26°F | 4.1" |
| Index | Hampden | Maine | National |
| Air quality index | 31 | 33 | 42 |
| Pollution index | 5,210,570 | 3,417,521 | 2,726,193 |
| Measurement | Total |
| Days measured | 361 |
| Days with good air quality | 348 |
| Days with moderate air quality | 13 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.020% |
| Benzene | 0.050% |
| Carbon Tetrachloride | 0.020% |
| Lead | 0.060% |
| Mercury | 0.020% |
| City | Population | Air Quality Index | National Avg. |
| Brewer, ME | 9,026 | 31 | 38.0% |
| Orono, ME | 9,523 | 31 | 38.0% |
| Bucksport, ME | 2,879 | 31 | 38.0% |
| Winterport, ME | 1,450 | 31 | 38.0% |
| Milford, ME | 2,356 | 31 | 38.0% |
| Hampden, ME | 4,373 | 31 | 38.0% |
| City | Population | Air Quality Index | National Avg. |
| Barnwell, SC | 4,373 | 47 | 6.0% |
| Okauchee Lake, WI | 4,373 | 37 | 26.0% |
| La Joya, TX | 4,374 | 42 | 16.0% |
| North Terre Haute, IN | 4,371 | 45 | 10.0% |
| Isle of Palms, SC | 4,371 | 38 | 24.0% |
| Hampden, ME | 4,373 | 31 | 38.0% |
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