WeatherStorm Team 5 Blog


Wednesday's Weather Word: Dew Point

Posted at 9:10 AM, Mar 29, 2017
and last updated 2019-03-26 10:19:04-04

We're getting into that time of year when you'll hear the local meteorologists talking a lot about the dew point temperature. The dew point represents the amount of moisture in the air and is actually a better indicator of how humid it feels than relative humidity. In the pictures below the teal represents dew points above 65° or higher relative humidity and the tan represents drier air. You can see that in the bottom picture it would seem that humidity would be low over south Florida, however that's not actually the case. South Florida feels muggy because of a high dew point temperature.

A good rule of thumb with the dew point temperature is if it's 65° or higher it will feel muggy outside.

The dew point especially affects us during the summer when heat index values come into play. The heat index value is how hot it actually feels outside when taking the actual temperature and dew point into account. This is a prime example of how the dew point is a better representation of comfort than relative humidity.

In the example above the relative humidity is higher so it would seem like the day would feel worse in that city. However you can see it's really the different dew point temperatures that make the biggest difference. The city with a dew point of 75°F and actual temperature of 90°F feels like 101­° while the city with the highest relative humidity feels much more comfortable.