In this hot steamy weather — it can be hard to keep your cool.

Officials warn that prolonged exposure to the heat can be harmful and potentially fatal.

New Yorkers are advised to drink plenty of water and limit strenuous activity, especially during the hottest parts of the day.

We spoke with a doctor at Lenox Hill Hospital who says heatstroke is a very real risk in these kinds of temperatures.

"The most important thing is to stay indoors, stay cool and stay hydrated," said Dr. Tracy Catlin, an attending in the emergency room. "It's important to know that when you feel thirsty, you're already dehydrated. People who are most at risk are the very young and the elderly."

Cooling centers across the city are open today and tomorrow.

For a full list of cooling centers and more hot weather tips visit the city's "Beat the Heat" web site.