Ahhh, the dog days of summer are upon us, and record-breaking heat has been impacting most of the country, and most of the northern hemisphere, for weeks now. Unfortunately, most of the population that has been under excessive heat alerts also happen to live in parts of the country that are very humid as well. Hot, humid weather is miserable, and unfortunately, there’s not a lot we can do to stay cool except with air conditioning. But why? What makes humid air so different than dry, hot air?
Evaporation
The answer lies in our need to evaporate away heat in order to keep our bodies cool. As the body heats up, our pores open up and hot, steamy moisture vents into the ambient air. When humidity levels are moderate or lower, much of this moisture is either evaporated or whisked away by gently-moving air. Remaining moisture on the skin serves to cool the skin and promote greater heat transfer as it comes into contact with air. This is why even a hot breeze feels great when it moves across sweaty skin.
However, air that has more than moderate levels of humidity contains a lot of moisture. Excessive moisture in the air prevents moisture from our bodies from being evaporated or carried away, and very high humidity will actually add moisture to our skin. Throw in high heat, and you have a recipe for misery, as well as a greater chance of suffering from heat exhaustion or heat stroke.
Because humid air inhibits our ability to radiate heat, temperatures as low as the mid-70s can feel much more miserable than in dry conditions where temperatures are 20 degrees higher. While people who are exposed to dry heat risk losing too-much moisture and suffering from dehydration, they also tend to sweat less and feel less-oppressed as well.
What Can We Do?
Aside from air conditioning, there’s little that can be done to make things more comfortable. The best thing is to get out of the sun and rest in a place that has moving air. Moving air will help to whisk away moisture and heat and provide minimal relief. When possible, sit in a room that has good cross-ventilation and run a couple of fans.
Experts suggest that windows should be cracked a few inches from the top to help heat escape whereas the bottom ones can be opened to promote circulation as well. Of course, all of this will depend on whether or not you have a breeze blowing or have access to fans at the time. You can also install window fans to blow hot air out, but then you also need a fan in the room to keep the air inside circulating.
In the event that you don’t have any fans, or can’t find circulating air, the next best thing is to cover yourself with cool, damp cloths, and replace them once they’ve started to warm up. You can also fan yourself or take turns fanning each other. As miserable as this sounds, it really helps, and it’s not hard to think of a situation during a heat emergency where this would be useful.
If you’re in the outdoors, find a gulley, ravine, cave or depression in the landscape. These areas usually have little micro-breezes that move cool air near the surface while the heat and humidity emitting from plants and tress moves up. Staying low can give you a temperature difference that can feel greater than 20 degrees. You can also cool off in a lake, stream or pool if you’re near one.
Finally, make sure that you limit physical activity until things cool down in order to minimize the amount of additional heat that your body generates. It will also reduce fatigue and the intensity of other heat-related ailments.
Hopefully, you’ll be able to minimize your exposure to hot, humid weather this summer. Make sure that you bring plenty of fluids when you’re out and about, and that you’re taking basic, common-sense precautions. If you do get stuck in a situation involving heat-related misery, try these suggestions out, and feel free to share any other tips and tricks that can help us all to stay a little bit cooler.
