What is the Heat Index and how does it affect our health?

While it’s the temperature that ends up on 10-day forecasts and electronic signs outside banks, the heat index is often a better indicator of the intensity of the heat, and the dangers it can present to people.

What is the heat index?

The heat index is a measure of how hot it really feels outside, when humidity and other factors are considered along with the temperature, according to Kimberly McMahon, a meteorologist with the National Weather Service. The heat index matters — and this is especially true in humid areas — because it includes the amount of moisture or humidity that’s in the air, and that moisture or humidity can make the air temperature feel even higher.

Why is the heat index used?

Aside from using it to provide a more accurate measure of what it feels like outside, the US National Weather Service relies on the heat index to let people know how much heat the human body can handle before it becomes dangerous.

Sometimes, if it’s humid enough, it doesn’t need to be that hot outside for the weather to be harmful. With the high humidity, it’s harder to have the human body sweat, and then have that sweat evaporate. The inability to

inefficiently cool off increases a person’s heat stress. For example, on a day when the temperature outside is 92 degrees and the humidity is 70 percent, the heat index is 112 degrees. When the heat index reaches that level, it’s dangerous, and it can cause sunstroke, muscle cramps, and heat exhaustion. For those doing physical activities or who are outside long enough under those conditions, heatstroke is also a risk.

The National Weather Service uses heat index values to know when to issue heat advisories, watches, and warnings, which urge residents in an area to avoid being outside during the hottest parts of the day.

How common are heat-related illnesses?

Weather-related deaths and injuries are often associated with more drastic events like tornadoes and hurricanes, but heat-related illnesses are the leading cause of death related to weather or environmental events, according to the American Public Health Association.

Every year, more than 600 people across the country die because of extreme heat, according to the Centers for Disease Control and Prevention. Regardless of whether someone lives in an area where they are accustomed to the heat, it’s important to pay attention to heat-related watches and warnings when they are in effect.

People need to always pay attention to the heat index and take it seriously because it is the No. 1 weather-related killer in the United States.

Seamlessly monitor key environmental conditions and be notified when the heat index can affect you and your family's health?

The Butterfly’s intelligence calculates the heat index based on temperature and humidity measurements and automatically provides you with notifications when appropriate. Temperature and Humidity measurements are made every 10 minutes on all applications by default, but can easily be changed using the Conscious App.