1.1 Level 0: Summer preparedness – long term planning
Year-round joint working to reduce the impact of climate change and ensure maximum adaptation to reduce harm from heatwaves. This involves influencing urban planning to keep housing, workplaces, transport systems and the built environment cool and energy efficient.
1.2 Level 1: Summer preparedness
Summer preparedness runs from 1 June to 15 September when a Level 1 alert will be issued. The heatwave plan will remain at Level 1 unless a higher alert is triggered. During the summer months, social and healthcare services need to ensure that awareness and background preparedness are maintained by implementing the measures set out in the heatwave plan.
1.3 Level 2: Heatwave is forecast – alert & readiness
This is triggered as soon as the Met Office forecasts that there is a 60 per cent chance of temperatures being high enough on at least two consecutive days to have significant effects on health. These vary from region to region, but the average threshold temperature is 30ºC during the day and 15ºC overnight. This forecast will normally be issued 2–3 days before the event is expected. As death rates rise soon after temperature increases, with many deaths occurring in the first two days, this is an important stage to ensure readiness and swift action to reduce harm from a potential heatwave.
1.4 Level 3: Heatwave action
This is triggered as soon as the Met Office confirms that threshold temperatures have been reached in one or more regions. This stage requires specific actions targeted at high-risk groups.
1.5 Level 4: National emergency
This is reached when a heatwave is so severe and/or prolonged that its effects extend outside health and social care, such as power or water shortages, and/or where the integrity of health and social care systems is threatened. At this level, illness and death may occur among the fit and healthy, and not just in high-risk groups and will require a multi-sector response at national and regional levels.
The decision to go to a Level 4 is made at national level and will be taken in light of a cross-government assessment of the weather conditions, co-ordinated by the Civil Contingencies Secretariat (Cabinet Office).