What's the difference between heat health alerts and extreme heat warnings?

Many parts of the UK are experiencing a heatwave.

While a lot of people would describe an ordinary period of very warm or hot weather as a heatwave, the Met Office - the UK's official weather service - has a very formal set of criteria.

It needs locations to reach a particular threshold temperature for at least three consecutive days and that varies from 25C (77F) across the north and west of the UK, to 28C (82.4F) in parts of eastern England.

The UK has two types of warnings to try to increase awareness around risks of hot weather.

The UK Health Security Agency (UKHSA) has a Heat-Health Alert system for England, external.

Working with the Met Office, these alerts are a sort of early warning system for health and social care professionals who are in the frontline when it comes to dealing with heat-related health risks, especially for vulnerable people. They aren't aimed at the public but can be freely accessed by anyone.

While focus may be on the daily maximum temperatures, a lot of consideration is also given to those overnight which can have important impacts on how our bodies deal with heat.

Starting at yellow, the alerts can be escalated to amber or the most severe, red.

The other warning you might hear about are "extreme heat warnings" which are issued by the the Met Office and aimed at the public.

They are part of the wider severe weather warning service and generally issued to highlight the potential effects of heat in order to protect lives and property by helping people to make better decisions and to stay safe.

These could be issued anywhere across the UK and are either amber or red.

A red warning would signify a risk to life, even for healthy and young people with impacts to infrastructure as well.

The first time a red extreme heat warning was issued in the UK was during the intense heatwave of 2022 when a new record of 40.3C (104.5F) was recorded in Coningsby, Lincolnshire.