Catoctin Mountain Park, and the surrounding area, generally experiences a mild, four-season climate, but can experience extreme weather at times. Precipitation in the area is approximately 44 inches per year with monthly distribution being fairly even throughout the year. Snowfall fluctuates from year to year, but averages 35 inches per year. In 1996 over 82 inches of snow fell, while only 6 inches fell in 1992. Summers are usually warm, with temperatures averaging 80 degrees Fahrenheit, but can exceed temperatures over 90 degrees. Winter temperatures average around 30 degrees Fahrenheit, but lows have been recorded at -10 degrees! Spring and fall seasons are more unpredictable, with milder temperatures and frequent gusts of wind.

In summer of 1998 the park experienced a brief spell of extreme weather. During a thunderstorm a microburst struck an area on the west side of Park Central Road. A microburst is a strong, downward force of air that can cause tornado-like damage to the area it strikes. A microburst can leave a debris path up to half a mile! The Catoctin microburst was concentrated in a single area and tore up approximately 4 acres of forest.