I like to use the analogy of a windowless spaceship returning to Earth after a long voyage. It lands in Washington, but the crew has no idea what season it is. A garbled radio message informs the crew only that the relative humidity is 75 percent. What kind of weather should they dress for? Many might say warm, humid weather. They would not necessarily be right, however, as the outside air temperature could be 20 degrees Fahrenheit and it could be the middle of winter.
July 12, 2017 at 12:10 PM EDT