Throughout the summer and winter, UKHSA and the Met Office monitor the weather forecast to help health and social care professionals, emergency services, the voluntary sector and the public prepare for adverse conditions. If particularly hot or cold weather is forecast, we will carry out joint risk assessments and issue alerts where necessary.
UKHSA’s Weather-Health Alerts (WHA) is separate from the Met Office. National Severe Weather Warning Service (NSWWS) – It is important to understand the differences.
Weather-Health Alerts specifically focus on the impact of weather on health. It is primarily aimed at the health and social care sector and first responders, although it may be of interest to a wider audience. During WHA we remind the public to check in on friends and family who may be vulnerable due to age or health conditions.
The National Severe Weather Warning Service covers a wide range of weather hazards, such as flooding and storms, for a wider audience across the UK.
The key difference is that the UKHSA system includes a yellow alert, whereas the Met Office’s heatwave warnings start with amber. UKHSA’s yellow alert focuses on particularly vulnerable people, including older people and people with certain long-term health problems. At this level, action within health and social care settings is essential.
The two systems have slightly different targets and purposes, so they may issue ambers before the Met Office, but they are in constant contact throughout the warning/alert period to ensure there is a shared picture of the weather situation.
What do the different colors of the weather-health alert mean?
- Green (ready) – No alert is issued as the condition is likely to have minimal health effects. Business as usual. Summer or Winter Planning and Preparation Activities
- yellow (response) – These warnings cover a variety of situations. Yellow alerts may be issued during periods of heat or cold that are unlikely to affect most people but may affect particularly vulnerable people.
- Amber (enhanced response) – An amber alert indicates that weather impacts are likely to be felt across the health service and the entire population is likely to be at risk. Non-health sectors may also begin to see impacts and a more significant coordinated response may be needed.
- Red (emergency response) – A red alert indicates a serious risk to life, even for healthy people.
What triggers a weather-health alert?
UKHSA’s weather-health alert system was updated in June 2023. Previously, alerts would trigger when temperatures reached a certain threshold. The new system takes a more sophisticated approach by considering:
- Temperature threshold (known based on the health effects we have observed over the past few years)
- How long the weather situation is expected to last
- How many areas are affected?
- The situation may escalate
- Multiple hazards such as snow, ice, wind or flooding
- If the system is already under strain for other reasons, such as hospitals already experiencing high demand.
These changes reflect the latest evidence on how temperature affects mortality, the impacts observed on health and social care systems during recent heatwaves, and long-term weather trends in regions of the UK.
cold health warning
The Bureau of Meteorology does not issue low temperature warnings as part of the NSWWS. Instead, it issues warnings for high-impact weather conditions, including rain, fog, wind, thunderstorms, snow and ice.
UKHSA takes a different approach. We take cold temperatures into account explicitly through our cold health warnings and assess this alongside other factors as part of the dynamic risk assessment we carry out with the Met Office.
UKHSA and the Met Office remain in close contact throughout the winter to issue cold health warnings as quickly as possible. Met Office warnings influence decisions about alert levels.
Fever Health Reminder
There are two early warning systems for high temperatures in the UK.
- Heatwave Alert (HHA) issued by UKHSA
- Heat wave warning issued by the Bureau of Meteorology as part of NSWWS
Due to the generally higher temperatures in London, slightly different thresholds are used to issue heat warnings in that region.
Why do UKHSA’s weather-health alerts only apply to England?
The Met Office’s national severe weather warning service covers the whole of the UK. The weather-health warning only applies to England as responsibility is devolved in Scotland, Wales and Northern Ireland. Weather Health’s automated alert system allows users to specify which regions of the UK they would like to receive updates from.
How can I get notifications?
you can Sign up for weather-health alerts here or visit us data dashboard To see the current alert status across the UK, we also share alerts through our social media accounts.
you can Check the current UK weather warnings on the Met Office website..
Weather affects different people in different ways. Cold spells, which pose little risk to most of the population, can be dangerous to older adults and people with heart disease. Even heat waves that do not meet national weather warning thresholds may require urgent action in hospitals and nursing homes. By maintaining a dedicated weather-health warning system alongside the Met Office’s National Severe Weather Warning Service, we ensure that health and social care professionals receive targeted, actionable guidance, while the public continues to benefit from extensive weather warnings. Both systems work together to protect life.
