As tens of millions of residents remain under excessive heat warnings, concerns about heat-related illnesses rise.

The temperature on a summer day may be in the 80s or 90s. So why does it feel so much hotter? That's the heat index. Here's how it works.

If sweat strikes you as the ultimate summer threat, consider these strategic ways to still enjoy spending time outside on hot days.

Forecasters are expecting a prolonged and potentially dangerous heat wave over the next few days, raising health concerns. Here's how Southern Californians can stay cool.