HOUSTON — Here in Houston we know all about humidity and that sticky feeling when the temperatures go up along with the moisture content in the air.
It can feel like literally being hit in the face when you open the door. Somehow, it makes the high Texas temps feel worse. And while it feels uncomfortable, when extreme heat is combined with high humidity, it can be downright dangerous.
That’s all thanks to how our body cools off. When we get hot, we sweat. That sweat evaporates on our skin, cooling off our bodies.
Humidity, often measured by dew point, can interrupt that process. When the dew point is high, meaning there is more moisture in the air, the sweat on our skin has a harder time evaporating, making it harder for our bodies to cool off. And that can be deadly.
One way to track how dangerous it is outside is with the wet bulb temperature. It basically mimics how the human cooling system works.
It is named after an experiment where you wrap a wet cloth around the bulb of a thermometer. Water evaporating from the cloth will cool the thermometer. If the air around the thermometer is humid, it will be harder for that water to evaporate, making it harder to lower the temperature on that thermometer. When the wet-bulb temperature is 90 degrees, even people used to the heat can no longer safely carryout outdoor activities.