Transcript for Dangerous and widespread heat wave throughout US
We begin with that oppressive summer heat that's already gripping more than half the country forecasters say the dangerously hot humid conditions will break records it will likely last through the weekend watches and warnings have already been issued in at least 28 states. And the heat index or real thrill conditions will be well into the triple digits ABC's for us are Abby begins our coverage from Washington Ramona. You better feel heat down there. We share our Jeannette and Kenneth. Temperatures right here in the nation's capital already soaring and experts say the combination of sunshine high temperatures and humidity. Can prove life threatening in coming days with children and the elderly particularly vulnerable. This morning a dangerous and widespread heat wave spreading across much of the United States leaving more than 170. Million people. Exposed to the hottest weather of the summer. New York Philadelphia and the nation's capital. Already under a heat emergency the New York City hasn't seen a 100 degree temperature since 2012 I really think we'll get close this weekend. Meteorologists calling for DC's feels like temperatures to feel almost as hot as Death Valley and in the upper midwest Milwaukee's mayor getting the word out. About cooling stations. We're very very concerned about people would physical challenges we. We're concerned about the elderly were concerned about children. Meanwhile emergency rooms are on alert bracing for an influx of heat related emergencies the heat is really something that is. Can suffocate you you can develop some symptoms especially if you don't have a plan they heat and humidity already teach me. Told once in summer campers in Newington. Were seven children were brought to the hospital because of dehydration and heat exhaustion it's very important to hydrate your children two hours before they go to an event. The conditions particularly dangerous for outdoor workers. And although other work must go on John why Dell of superior roofing in Chicago says they still trying to take every precaution they can we let the guys take as many. Race is possible myself included make sure we are planning a water with a soft there. Again extreme heat can pose some serious safety concerns so it's important that you stay hydrated. Experts actually say that if you're feeling thirsty you're already dehydrated. Also you need to find a local cooling station a good idea is a public library or maybe an indoor mall. And remembered attack on your elderly neighbors and children as well since both again are particularly vulnerable to an antenna. Good information people to stay vigilant and this heat Mona thank you.
This transcript has been automatically generated and may not be 100% accurate.