You’ve probably heard the saying, “It’s not the heat, it’s the humidity!” Well, through the first several weeks of Summer in North Texas it’s been BOTH! Persistent southerly breezes have brought in a constant fetch of Gulf moisture into North Texas, and consequently very high humidity. Typically, our dew points, which are a more accurate depiction of how much moisture is in the air, are in the high 50s and 60s in Summer. But through much of June and July, they have stayed in the 70s, even during the peak heat of the day. On a few days, we had dew points as high as 80 degrees! So, looking at the chart above, if the air temperature is say, 100 degrees, and the dewpoint is at 76 degrees (which has been very common), the resulting heat index or “feels like temperature” is 116 degrees! That is stifling heat and humidity. The kind that makes you feel like you just stepped out of a hot shower! But, it’s not only uncomfortable, it can be dangerous, especially if you spend time exercising or doing physical activity during the afternoon and early evening. 

Why does the humidity stress our body so much? The main reason has to do with our body’s ability to cool itself, which occurs as we evaporate sweat off our skin. That’s because cooling your body via sweating relies on a principle of physics called “heat of vaporization.”