Freezing rain
The average seasonal snowfall is , but it varies greatly depending on the winter, with some seasons seeing minimal snow while others see several major Nor'easters. Due to lessened urban heat island (UHI) as compared to the city proper and distance from the moderating Chesapeake Bay, the outlying and inland parts of the Baltimore metro area are usually cooler, especially at night, than the city proper and the coastal towns. Thus, in the northern and western suburbs, winter snowfall is more significant, and some areas average more than of snow per winter. It is by no means uncommon for the rain-snow line to set up in the metro area. Freezing rain and sleet occurs a few times each winter in the area, as warm air overrides cold air at the low to mid-levels of the atmosphere. When the wind blows from the east, the cold air gets dammed against the mountains to the west and the result is freezing rain or sleet.