The UK Met Office provides the National Severe Weather Warning Service (NSWWS) to warn the public, businesses, and government of the impacts of severe weather, which have the potential to cause danger to life or widespread disruption. Warnings of rain, wind, snow, fog, ice, lightning, and thunderstorm are issued through the NSWWS. These warnings are given a colour depending on a combination of the severity of the impacts that could occur and the likelihood of those impacts happening.

A key priority of the Met Office is to continuously evolve and improve the quality and delivery of the NSWWS, to meet the needs of the UK. From the 1 June, in consultation with Public Health England (PHE), the Devolved Administrations (and their health agencies) and other key stakeholders, they are introducing an Extreme Heat Warning into the NSWWS.

The purpose of the extreme heat warning is to increase awareness of the negative impacts of heat on health, infrastructure, and other services for the public across the UK to enable better preparedness to maintain life, wellbeing, property, and livelihoods. UK extreme heat episodes are becoming more frequent, more prolonged and hotter and the impacts can be many and varied everything from increased traffic in coastal areas, increased energy use, increased risk of wildfire and problems for the transport network to added strain on the health service and premature deaths.

How will the Extreme Heat warning work alongside other heat services?

There are already a number of heat related services, alerts and definitions and the extreme heat warnings will complement and enhance these services and be consistent with each of the definitions. It will be applicable UK wide and will be based on a dynamic risk assessment with partners rather than fixed meteorological thresholds.

• Extreme Heat Warning – an impact-based warning designed to highlight the potential impacts of extreme heat to protect lives and property, helping people make better decisions to stay safe and thrive.
• Public Health England Heat Health Alert – An England only service considering the impact of prolonged extreme heat on public health, especially those with long-term health conditions.
• Heatwave definition – a threshold-based meteorological definition designed to provide the media and public with consistent and reliable messaging.

For summer 2021 any extreme heat warnings issued will be Amber or Red only, indicating Medium or High likelihood of Medium or High impacts. In England the warnings will be coordinated with the colour and general advice of the PHE Heat Health Alerts.

Please see our warning web page for more information on the impact of extreme heat.

Q: Why has an Extreme Heat Warning been introduced?

A. A key priority of the Met Office is to continuously evolve and improve the quality and delivery of weather warnings as it is an essential service for protecting life and property in the UK. A heat warning has been introduced to increase awareness of the negative effects of heat for the public and will complement the heat health service.

Q: What is an Extreme Heat Warning?

A: An Extreme Heat warning is an impact based warning designed to highlight the potential impacts of extreme heat, to protect lives and property and help people make better decisions to stay safe and thrive.

Q: Why are there two alerting/warning systems?

A: Each service has a different audience and combined, they provide maximum coverage across the UK and multiple sectors.  The PHE Heat Health Alert service considers the impact of prolonged extreme heat on public health, especially those more vulnerable to heat and is for England only.  The Extreme Heat Warning is an impact-based warning designed to highlight the potential negative impacts of extreme heat on the wider population to protect lives and property across England, Wales, Scotland and Northern Ireland. The Met Office, PHE and the devolved health agencies have agreed that having an Extreme Heat Warning will enable a significant amplification of public health messages should a severe or prolonged hot weather episode be forecast for the UK

Q: Are there any risks associated with having two alerting systems this year?  How will these be managed?

A. The Met Office and PHE will continue to work together to ensure the two systems are complementary to one another to avoid any confusion amongst frontline responders and the general public. This will also help ensure the maximum possible warning time.

Good situational awareness will be maintained between both organisations and other partners including Cabinet Office, NHS England and the devolved health agencies.

This summer, the Heat-Health Alerting system will operate as normal, with the established processes and risk assessments taking place based on the weather forecast from the Met Office.