Heat is a leading cause of weather-related fatalities each year. People and communities across the country experience heat impacts differently due to a combination of personal, environmental, physiological, and social factors.
What is Extreme Heat?
There are several ways to define extreme heat:
A period of high heat and humidity with temperatures above 90°F for at least two to three days.
A temperature that is much hotter and/or humid than average. Because some places are hotter than others, this depends on what’s considered average for a particular location that time of year. For example, while summertime temperatures of 100˚F might be normal for Phoenix, Arizona, they would be considered extreme for Seattle, Washington.
What is a Heat Wave?
A heat wave is a period of abnormally hot weather generally lasting more than two days. Heat waves can occur with or without high humidity. They have potential to cover a large area, exposing a high number of people to hazardous heat. Heat can be very taxing on the body – Learn more about heat-related illnesses
What is a Heat Dome?
A heat dome is an exceptionally hot air mass that develops when high pressure aloft prevents warm air below from rising, thus trapping the warm air as if it were in a dome. One of the most famous recent heat domes took place in the Pacific Northwest in 2021, which broke temperature records for the region and led to over 1,000 heat-related emergency department visits…
Source: HEAT.gov | Science and Information to Reduce Heat Risk
