"The Post is tracking the potential for dangerous heat using the heat index, which accounts for the combined impact of temperature and humidity — the higher the humidity, the more difficult it is for the body to cool itself off through sweating.
Extreme heat kills more people in the United States than any other weather hazard, and the risk of longer and more frequent heat waves is only expected to increase as climate change worsens. Heat disorders such as heat stroke, heat cramps and heat exhaustion are possible with any extended exposure to a heat index at or above 90 degrees.
Heat illness can set in quickly — in as little as 10 to 15 minutes — when your body overheats and can’t properly cool itself off. This can lead to muscle cramps or spasms, heavy sweating, weakness or tiredness, abnormal pulse rate, dizziness, nausea, vomiting, headache, confusion, fainting, loss of consciousness or death."
Advertisement 
