May arrived today with another in a string of gorgeous spring days - cool and dry and gloriously sunny. It will not last. May is arguably the beginning of summer in Maryland, a month that can bring truly hot weather. And humidity. Remember humidity? Here's the scoop:

The average temperature at BWI in May is 62.9 degrees. The average daytime high rises from 69 to 79 degrees by month's end. And the average overnight low climbs from 47 to 57 degrees. But more extreme weather is quite possible.

The record daily highs in May are almost exclusively in the 90s. Only May 1 and 2 still have record highs in the 80s. Few of us will remember them, but the hottest May days all reached 98 degrees: on May 19, 1962; May 22, 1941; May 23, 1925; and on May 30, 1991.

The coldest May day was on the 11th, in 1966, when the low was 32 degrees. And yes, it can still snow in May in Baltimore. The latest snowfall ever recorded was on May 9, 1923, when just a trace was noted in the city. It also snowed - a trace - on May 1, 1963.

The average precipitation in May at BWI is 3.89 inches. The wettest May on record there was 8.71 inches, recorded in 1989. The driest was just three years earlier, in 1986, when just 0.37 inch fell.