Relative humidity measures how much moisture is in the air compared to how much it could hold at a given temperature. It is simply the dew point temperature divided by the air temperature, times 100.

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 ...

Good news: a weather forecast of 100 percent humidity doesn’t always mean it’s going to rain. Bad news: It might feel absolutely disgusting outside. The percentage of humidity is not measured by the ...