Heat wave

heat wave

Prolonged period of excessively hot weather

A heat wave or heatwave, sometimes described as extreme heat, is a period of abnormally hot weather that lasts for multiple days. A heat wave is usually measured relative to the usual climate in the area and to normal temperatures for the season. The main difficulties with this broad definition emerge when one must quantify what the 'normal' temperature state is, and what the spatial extent of the event may or must be. Temperatures that humans from a hotter climate consider normal can be regarded as a heat wave in a cooler area. This would be the case if the warm temperatures are outside the normal climate pattern for that area.

Also known as...heatwave, extreme heat, and extreme hot weather
UK Braces for Third Heatwave of 2026

UK Braces for Third Heatwave of 2026 The UK is set to face another heatwave with temperatures up to 39C, prompting a yellow heat health alert.