ROCHESTER, N.Y. – Wind direction plays a crucial role in determining daily temperatures—especially in regions like Western New York. A northerly breeze coming off Lake Ontario often brings cooler air into Rochester. But when the wind shifts and blows from the south, the outcome is quite different. That is when we experience what meteorologists call “downsloping”—a warming effect as air descends from higher elevations.A prime example of this effect occurs in the Bristol Hills, just south of Rochester. Normally, as you move higher into the atmosphere, temperatures decrease. But under dry conditions, the dry adiabatic lapse rate comes into play. This is a meteorological principle that states in a dry atmosphere, air warms at a rate of 5.5 degrees Fahrenheit for every 1,000 feet it descends.

Let’s apply this to a local scenario. Bristol Mountain, at its summit, reaches roughly 2,100 feet above sea level. In contrast, the Rochester Airport elevation is about 541 feet. That’s a difference of approximately 1,600 feet. If a parcel of air starts at the top of Bristol at 55 degrees Fahrenheit and begins to descend due to strong southerly winds, it will warm significantly. By the time it reaches Rochester, the temperature of that air could rise to about 63 degrees Fahrenheit—an increase of 8 degrees purely due to the mechanics of downsloping.

This phenomenon helps explain why certain days can feel unseasonably warm, even when surrounding regions stay cooler. It is just one more example of how local geography and atmospheric dynamics interact to shape our weather.