Seasonally, Savannah tends to have hot and humid summers with frequent (but brief) thunderstorms that develop in the warm and tropical air masses, which are common. Although summers in Savannah are frequently sunny, half of Savannah's annual precipitation falls during the months of June through September. Average dewpoints in summer range from . Winters in Savannah are mild and sunny with average daily high temperatures close to . November and December are the driest months recorded at Savannah–Hilton Head International Airport. Each year, Savannah reports 24 days on average with low temperatures below freezing, though in some years fewer than 10 nights will fall below freezing. Although decades might pass between snowfall events, Savannah has experienced snow on rare occasions, most notably in December 1989, when up to was recorded in one day in parts of the city.