| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 21°F | 41°F | 32°F | 3.4" |
| February | 21°F | 41°F | 31°F | 3.0" |
| March | 27°F | 48°F | 38°F | 3.8" |
| April | 37°F | 59°F | 48°F | 3.9" |
| May | 46°F | 67°F | 57°F | 3.8" |
| June | 56°F | 77°F | 67°F | 4.4" |
| July | 64°F | 83°F | 73°F | 3.5" |
| August | 61°F | 82°F | 72°F | 3.0" |
| September | 55°F | 76°F | 66°F | 3.9" |
| October | 44°F | 66°F | 55°F | 5.2" |
| November | 34°F | 56°F | 45°F | 3.3" |
| December | 27°F | 47°F | 37°F | 4.8" |
| Index | Mattituck | New York | National |
| Air quality index | 41 | 43 | 42 |
| Pollution index | 4,117,250 | 6,179,275 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 280 |
| Days with moderate air quality | 71 |
| Days w/ poor A.Q. for sensitive groups | 12 |
| Days with unhealthy air quality | 2 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.050% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.010% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Sag Harbor, NY | 1,959 | 37 | 26.0% |
| Wainscott, NY | 342 | 37 | 26.0% |
| Shelter Island, NY | 1,980 | 37 | 26.0% |
| East Marion, NY | 1,144 | 37 | 26.0% |
| Orient, NY | 1,023 | 37 | 26.0% |
| Mattituck, NY | 4,898 | 41 | 18.0% |
| City | Population | Air Quality Index | National Avg. |
| Long View, NC | 4,898 | 43 | 14.0% |
| Houlton, ME | 4,897 | 31 | 38.0% |
| Mount Pleasant, TN | 4,899 | 31 | 38.0% |
| Meadows Place, TX | 4,899 | 52 | 4.0% |
| Davison, MI | 4,896 | 38 | 24.0% |
| Mattituck, NY | 4,898 | 41 | 18.0% |
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