| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 18°F | 35°F | 27°F | 0.8" |
| February | 18°F | 35°F | 26°F | 1.2" |
| March | 26°F | 45°F | 35°F | 1.7" |
| April | 37°F | 59°F | 47°F | 2.1" |
| May | 48°F | 71°F | 59°F | 2.9" |
| June | 58°F | 78°F | 67°F | 3.1" |
| July | 62°F | 83°F | 72°F | 3.4" |
| August | 60°F | 80°F | 69°F | 2.9" |
| September | 53°F | 75°F | 63°F | 2.8" |
| October | 44°F | 62°F | 52°F | 3.2" |
| November | 33°F | 50°F | 41°F | 1.3" |
| December | 25°F | 39°F | 32°F | 1.7" |
| Index | Romulus | New York | National |
| Air quality index | 34 | 43 | 42 |
| Pollution index | 2,885,140 | 6,179,275 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 358 |
| Days with moderate air quality | 7 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.004% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.005% |
| Lead | 0.010% |
| Mercury | 0.002% |
| City | Population | Air Quality Index | National Avg. |
| Ovid, NY | 505 | 34 | 32.0% |
| Lodi, NY | 305 | 34 | 32.0% |
| Trumansburg, NY | 1,673 | 34 | 32.0% |
| Aurora, NY | 675 | 34 | 32.0% |
| Penn Yan, NY | 5,223 | 34 | 32.0% |
| Romulus, NY | 446 | 34 | 32.0% |
| City | Population | Air Quality Index | National Avg. |
| Fruithurst, AL | 446 | 43 | 14.0% |
| Havana, AR | 446 | 36 | 28.0% |
| Bellflower, IL | 446 | 42 | 16.0% |
| Orient, IL | 446 | 43 | 14.0% |
| Pine Point, MN | 446 | 33 | 34.0% |
| Romulus, NY | 446 | 34 | 32.0% |