According to the Köppen climate classification system, Mount Marcy has a Warm-summer, Humid continental climate (Dfb). Dfb climates are characterized by a least one month having an average mean temperature ≤ , at least four months with an average mean temperature ≥ , all months with an average mean temperature . Since 1981 at Mount Marcy (elevation ), the highest air temperature was on 08/03/1988, and the highest daily average mean dew point was on 08/01/2006. Since 1981, the wettest calendar day was on 09/16/1999. During the winter months, the average annual extreme minimum air temperature on Mount Marcy (elevation ) is . Since 1981, the coldest air temperature was on 01/27/1994. Episodes of extreme cold and wind can occur with wind chill values < . The average annual snowfall total (Sep-May) is ≈ .