Heat Wave

weather · extreme heat · climate

What makes it extreme. A heat wave isn't just about hot weather, it's about temperatures that are much hotter than normal for your area. The same temperature that feels normal in Arizona might be a dangerous heat wave in Alaska.

Location matters most. Heat waves are measured by comparing temperatures to what's usual for that specific place and time of year. So a 90-degree day in cool Scotland could be a heat wave, while the same temperature in hot Texas might be a typical summer day.

It has to stick around. The key to a heat wave is that the abnormally hot weather lasts for multiple days in a row. A single hot day doesn't count, but several days of unusual heat does.

Different everywhere. There's no single temperature that makes a heat wave everywhere on Earth. Scientists have to decide what 'normal' means for each region before they can say if it's experiencing extreme heat.