Whether a summer day is great or awful often comes down to the humidity.

Across much of the world, hotter days are no longer arriving alone. The air itself is changing, sometimes turning from dry oven to steam bath, other times drying out even as thermometers climb. As ...

The first major heat wave of summer has enveloped much of the midwestern and eastern U.S. in a brutal “dome” of record temperatures and high humidity. The dome phenomenon happens when weather ...