The temperature on any given summer day may be in the 80s or 90s. So why does it feel so much hotter and oppressive at times? That's the heat index doing its thing. Here's how it works: What is the ...

Some hot days feel even worse thanks to high humidity, trapped heat and dew points. Cities are especially vulnerable. By Nazaneen Ghaffar Nazaneen Ghaffar is a reporter on The Times’s weather team. It ...

Across much of the world, hotter days are no longer arriving alone. The air itself is changing, sometimes turning from dry ...

Has this summer been muggier than usual? For nearly two-thirds of the country, the answer is yes. Tens of millions of Americans in the central and eastern United States have suffered from an ...