| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 25°F | 41°F | 33°F | 2.7" |
| February | 25°F | 42°F | 33°F | 2.3" |
| March | 32°F | 50°F | 40°F | 3.3" |
| April | 42°F | 60°F | 51°F | 3.7" |
| May | 52°F | 70°F | 60°F | 3.4" |
| June | 61°F | 78°F | 69°F | 4.3" |
| July | 68°F | 84°F | 76°F | 3.2" |
| August | 66°F | 83°F | 74°F | 3.4" |
| September | 60°F | 76°F | 68°F | 3.2" |
| October | 50°F | 66°F | 57°F | 3.5" |
| November | 39°F | 55°F | 47°F | 2.5" |
| December | 32°F | 46°F | 39°F | 4.5" |
| Index | Greenlawn | New York | National |
| Air quality index | 43 | 43 | 42 |
| Pollution index | 39,208,800 | 6,179,275 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 262 |
| Days with moderate air quality | 82 |
| Days w/ poor A.Q. for sensitive groups | 18 |
| Days with unhealthy air quality | 3 |
| Pollutant | Total |
| Arsenic | 0.060% |
| Benzene | 0.320% |
| Carbon Tetrachloride | 0.020% |
| Lead | 0.320% |
| Mercury | 0.130% |
| City | Population | Air Quality Index | National Avg. |
| Darien, CT | 22,334 | 43 | 14.0% |
| Stamford, CT | 133,529 | 43 | 14.0% |
| Dix Hills, NY | 24,498 | 43 | 14.0% |
| Centerport, NY | 5,989 | 43 | 14.0% |
| Elwood, NY | 11,955 | 43 | 14.0% |
| Greenlawn, NY | 15,169 | 43 | 14.0% |
| City | Population | Air Quality Index | National Avg. |
| Scottsbluff, NE | 15,165 | 19 | 62.0% |
| Hereford, TX | 15,173 | 44 | 12.0% |
| Grovetown, GA | 15,176 | 47 | 6.0% |
| Yankton, SD | 15,183 | 36 | 28.0% |
| Hampton Bays, NY | 15,184 | 41 | 18.0% |
| Greenlawn, NY | 15,169 | 43 | 14.0% |