Baltimore 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. Spring and autumn are warm, with spring being the wettest season in terms of the number of precipitation days. Summers are hot and humid with a daily average in July of , and
Hail hailstones, described as between the size of bumble bees and ping pong balls, were accompanied by rain and high winds. The hail fell in only the one area, leaving the surrounding area untouched. It fell for one and a half hours between 10 p.m. and 11:30 p.m. A meteorologist for the National Weather Service in Boulder said, "It's a very interesting phenomenon. We saw the storm stall. It produced copious amounts of hail in one small area. It's a meteorological thing." Tractors used to clear the area filled more than 30 dump-truck loads of hail. Research focused on four individual