Heat can be dangerous, but health experts say there are ways to manage the threat.

Scorching temperatures, especially combined with high humidity, pose risks particularly for children, older people and those with certain health conditions. Anyone can suffer from heat-related illness.

Climate change is also exacerbating heat waves and heat stress.

So here are some tips to stay safe:

When heat becomes dangerous
Dangers posed by hot weather depend on more than the temperature. The most detailed measurement is called the wet bulb globe temperature (WBGT), which includes temperature, humidity, cloud cover and wind. The heat index, which measures temperature and humidity, is less descriptive but easier to find on weather apps. Both explain why a shaded soccer field on a 90 degree F day (32 degree C) in arid Phoenix may be less risky than an exposed park on an 80 degree F (27 degree C) day in soupy Little Rock.

Just based on heat index, NOAA has a chart that calculates how dangerous prolonged exposure can be. For example, a day in which temperatures reach 96 degree F (36 degrees C) and 45% humidity would fall into the "danger" category for prolonged exposure or strenuous activity.

The WBGT threshold isn't exact, but recent research suggests that even some young, healthy people can't endure hours of exposure to high heat and humidity.

How to cool down
Overnight temperatures can be a particularly dangerous part of a heat wave, said Ashley Ward, director of the Heat Policy Innovation Hub at Duke University.

"Your body needs a reprieve," she said. "You don't get that overnight, we start the next day at a deficit." Heat can worsen labor productivity and lead to more visits to the emergency room.

"When we have overnight temperatures that don't drop below 75 degrees" F (24 degrees C), she said, "you start to see some pretty extraordinary outcomes with respect to heat illness and heat stroke, and even mortality."

Ward said air conditioning can help, but she acknowledged that not everyone has access...