A Thursday Scorcher

As of 1 p.m. Bradley Airport reached 94 degrees. When you combine the temperature and humidity the heat index is 104!

Heat index is what we use in the summer to express the “apparent” temperature or what it feels like to the human body. Another “apparent” temperature you may be familiar with is the wind chill which is used in winter.

Humans cool through the evaporation of sweat off the skin (evaporational cooling removes heat from the skin). When the atmosphere is very humid the rate of evaporation is less and therefore less evaporational cooling. The net effect is a warmer body. Today even though the heat index is quite high a strong southwesterly breeze may mute the impact somewhat as the gusty wind leads to more evaporation than  you would typically expect on a day this humid.

Here’s a chart that allows you to calculate the heat index based on temperature and dew point.

Heat Index: Courtesy National Weather Service

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