Aug 04 2011
Ladies of my grandmothers’ generation never felt hot and sweaty. They may have perspired but they never called it sweat. Instead they “felt dewy.”
We’ve all been feeling dewy lately. The humidity has been so thick in Pittsburgh that we’ve been cloaked in haze for days. When we step out the front door at dawn it feels hot even though it’s only 73oF.
Temperature has been no guide when choosing what to wear. 73oF outdoors is oppressive; 73oF on an air conditioned bus is freezing!
My niece Kelley, who grew up in south Florida, gave me a tip on what to listen for in the weather report: Dewpoint is the number to watch. If it’s 70oF or more you’re going to feel hot.
The dew point is the saturation temperature, the point at which dew will form if the air pressure remains constant.
Our bodies cool by evaporating perspiration from our skin. When the dewpoint is over 70oF we perspire but the dampness doesn’t evaporate and we still feel hot. The weather’s oppressive even though the temperature sounds comfortable.
Since Kelley told me about dewpoint I’ve been paying attention to it. This morning it was 69oF.
(photo by Sam Leinhardt)