WEATHER MINUTE: What is dew point?

Posted: 9:51 AM, May 20, 2016
Updated: 2016-05-20 09:51:10-04

To do or not to do!?

OK, the spelling's different, but today's Weather Minute is about "dew point," a measure we use a lot, especially from spring to fall, to quantify the amount of moisture in the air.

First, here's the definition: "the temperature to which air must be cooled to become saturated to allow... DEW to form.

More to the point, the higher the dew point reading, the more moisture is in the air and the more humid it feels.

A dew point of 50 or less is dry, even 55 is comfortable. When the dew point climbs to 60, most people say humidity is a factor, by 65 it's muggy and 70 or higher is tropically oppressive.

Dew points are often higher on one side of a front than another, so air often gets drier or muggier when fronts pass.

Relative humidity involves moisture content also, but it changes drastically as temperatures warm and cool, so it's a lousy way to monitor moisture content. When moisture in the air is constant, relative humidity plunges during the day.

So, stick with the dew point, even when it gets sticky outside... especially then.