| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 18°F | 35°F | 26°F | 3.6" |
| February | 17°F | 33°F | 24°F | 1.3" |
| March | 20°F | 39°F | 30°F | 2.4" |
| April | 35°F | 60°F | 47°F | 5.3" |
| May | 44°F | 67°F | 55°F | 3.1" |
| June | 58°F | 79°F | 68°F | 7.7" |
| July | 63°F | 83°F | 72°F | 5.6" |
| August | 59°F | 80°F | 69°F | 6.2" |
| September | 51°F | 72°F | 61°F | 2.1" |
| October | 41°F | 58°F | 48°F | 5.9" |
| November | 34°F | 51°F | 42°F | 4.8" |
| December | 23°F | 36°F | 30°F | 2.8" |
| Index | Nelliston | New York | National |
| Air quality index | 27 | 43 | 42 |
| Pollution index | 1,674,650 | 6,179,275 | 2,726,193 |
| Measurement | Total |
| Days measured | 359 |
| Days with good air quality | 349 |
| Days with moderate air quality | 10 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.005% |
| Lead | 0.004% |
| Mercury | 0.002% |
| City | Population | Air Quality Index | National Avg. |
| Cherry Valley, NY | 586 | 27 | 46.0% |
| St. Johnsville, NY | 1,866 | 27 | 46.0% |
| Caroga Lake, NY | 410 | 27 | 46.0% |
| Sharon Springs, NY | 616 | 27 | 46.0% |
| Fort Plain, NY | 1,837 | 27 | 46.0% |
| Nelliston, NY | 691 | 27 | 46.0% |
| City | Population | Air Quality Index | National Avg. |
| Godley, IL | 691 | 0 | 100.0% |
| Dana, IN | 691 | 45 | 10.0% |
| Verona, MO | 691 | 39 | 22.0% |
| Riegelwood, NC | 691 | 34 | 32.0% |
| North Creek, NY | 691 | 36 | 28.0% |
| Nelliston, NY | 691 | 27 | 46.0% |
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