MSN.com (June 24) -- The impact of weather on a baseball game may not always be as immediately recognizable as a heavy storm causing a rain-out, but it can be profound even on a bright, sunny day. “For a long fly ball, a ball hit with a sort of home-run trajectory, that’s a ball that’s hit at about 100 mph off the bat, maybe at a 30-degree elevation angle,” says Alan Nathan, an emeritus professor of physics at Illinois.