Orlando – Approaching summer, you may notice terms like heat index or real-feel temperatures being included in the local weather broadcasts.
Often, viewers ask, “If it feels like 102 degrees, then why don’t you just say it’s going to be 102 degrees in the forecast?”
Air temperature and heat index are two different values. The heat index is an apparent temperature, which we will get into, but both values are equally important in a forecast, especially when it comes to your health.
The difference between temperatures and real-feel temperatures are not to hype up the heat forecast for entertainment. It’s mentioned because it can have extreme and even deadly impacts on the human body.
A thermometer is able to measure the physical amount of heat within a substance. It’s how the temperature of the air is measured. The air around us consists of gas molecules, which are combinations of two or more atoms. They’re not visible to the naked eye, but if you could see them, you would see the molecules constantly moving all over at very high speeds.
As they move, they collide with one another and with solid surfaces. The temperature of the air is a measure of how quickly the molecules are moving. Think of it like this: the more energy the molecules have, the higher the temperature. The slower they move, the lower the temperature.
Makes sense right? But that measurement may not represent how it feels outside. That’s where the heat index comes in handy.
Heat index values aren’t some made-up number. It’s the apparent temperature, or what we as humans perceive it to feel like to our bodies when relative humidity is combined with the temperature. Check out this chart below from the National Weather Service.
Fun fact, these values are for the shade. When exposed to direct sunshine, the heat indices will be higher.
Why does this matter? Two words: your health.
The human body sweats in order to regulate body temperature when exposed to heat. Sweating is a good thing as it helps cool the skin through the process of evaporation which keeps our bodies at a temperature that our organs can function normally under. Think of it as a natural air conditioner for the body. It’s what keeps us comfy. As the sweat evaporates off the skin, it causes the skin to cool down.
When humidity is added to the equation, this is where our bodies run into problems. When there’s more moisture in the air, the rate at which the sweat evaporates off the skin decreases. If the air mass around us is drier, the body will feel cooler even in high heat. That’s why desert heat, although very hot, doesn’t feel as uncomfortable as tropical heat.
When sweat doesn’t evaporate from the skin to cool it down, the body thinks it’s still hot and produces more sweat, forcing your body to work harder and making it difficult to regulate its temperature. This can lead to heat-related illnesses like heat stroke.
During 2018–2020, a total of 3,066 heat-related deaths occurred, according to the CDC. A previous study conducted from 2004-2018 showed that over 10,000 deaths in the United States were attributed to heat from May to September.
On average in the United States, over 700 heat-related deaths occur each year. Add to that over 67,000 emergency department visits and over 9,000 hospitalizations are due to heat. That’s a big impact.
We want you to stay safe. Here are some tips to stay healthy when heat indices soar.
1. Stay hydrated. Drinking a good amount of water will help keep body temperature regulated and prevent dehydration.
2. Take breaks. This means giving your body some time to relax when outside working or when kids are playing.
3. Take a break in the shade to cool down. Whether participating in activities in the backyard or lounging at the beach, your body needs some time out of the direct sunshine. This can be done under a tree, umbrella, porch or, better yet, inside with air conditioning. It will also help prevent sunburns.
4. Wear appropriate clothing. Think light. Lightweight, light colors and loose-fitting clothing is best. Not only will this type of clothing allow your body to breathe, but the light colors reflect the sun, unlike dark colors that absorb the heat.
5. Avoid hot and heavy meals. This type of food can actually add heat to the body, which results in the body working harder to stay cool.
6. Timing is everything. Try to plan outdoor activities earlier or later in the day. Peak heating happens around 3-4 p.m. Consider the time after noon as time the heat is building to reach the high temperature and then it slowly goes down as the sun reaches a lower point in the sky.
7. Don’t forget about pets. They need proper shelter from the direct sunshine and water to beat the heat, too.
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