From 1am on Wednesday 24 June, the UK Health Security Agency (UKHSA) had a red heat-health alert in place for six regions of England, including London, the South East and the East of England. A red alert means a risk to life for even the healthy population, and it also means a hot kitchen or cold room is no longer just uncomfortable. It is a food safety and staffing problem at the same time.
UKHSA described it as the second red heat-health alert ever issued, the first having come in July 2022. Summer is nearly over, but the alerting season runs to the end of this month and the lessons carry straight into next year, so this is a good week to go through what the system says and what it asks of a commercial kitchen.
How the heat-health alert system works
The Heat-Health Alerts are issued by UKHSA in partnership with the Met Office. The Weather-Health Alerting System guidance says the core alerting season runs from 1 June to 30 September, and that an extraordinary alert can be issued outside it if the criteria are met. That is what happened this year, when the first amber alert of 2026 went out on 22 May.
UKHSA's user guide sets out four levels. Green means no alert is issued because conditions are likely to have minimal impact on health. Yellow is for heat that would be unlikely to affect most people but could affect those who are particularly vulnerable. Amber means impacts are likely to be felt across the whole health service, and that non-health sectors may also start to see effects. Red is a significant risk to life for even the healthy population, with a coordinated response essential across all sectors.
The alerts are written for the health and social care sector first. They are not a trading rule, and nobody is told to close. But they are the clearest early warning a hospitality or food business gets that the next few days will be hard on equipment.
What a red alert says about businesses
When UKHSA issued the red alert on 22 June, it said that a red heat-health alert "indicates that a severe heatwave could have impacts beyond health and social care with potential effects on transport systems, food, water, energy supplies and businesses". The same sentence says it "indicates a risk to life for even the healthy population".
Food and energy supplies are on that list for a reason. A heatwave pushes up demand for cooling at exactly the moment the equipment doing the cooling is working hardest. UKHSA's own hot weather advice includes a line any kitchen manager can act on: "check that fridges, freezers and fans are working properly". The alert was extended and then stepped down, from red to amber on 26 June, which is a reminder that conditions can run for days rather than hours.
What heat does to kitchens, cold rooms and display chillers
Every refrigeration system moves heat from inside the box to the outside air. The condenser does the rejecting, and it works against whatever the air around it is doing. When that air is very hot, or when the condenser is sitting in a plant area, courtyard or rooftop pocket that has trapped heat, the system has to work harder to reach the same cabinet temperature. A coil furred with dust and grease makes it worse, because less heat gets out.
The legal line is on the food, not the air. In GOV.UK's food hygiene guidance for businesses, chilled food must be kept at 8°C or below, which is a legal requirement in England, Wales and Northern Ireland. The guidance also says to set your fridge to 5°C or below so food stays cold enough even if the temperature changes. Chilled food can stay out of the fridge for up to 4 hours, then you must throw it away. In a heatwave a prep room can burn through that margin quickly.
The practical points we would put in front of any kitchen during a hot spell:
- Door discipline. Walk-in doors left open while someone loads a delivery let warm, humid air straight in. Keep doors shut between trips, and batch what goes in and out.
- Clear the condenser. Keep boxes, bins and stored stock away from condensers and their airflow. Give plant spaces ventilation if you can.
- Clean the coils. A dirty condenser coil makes a system work harder in hot weather, and cleaning it is part of a proper service.
- Do not overload. Packing a cabinet or cold room so air cannot circulate leaves warm pockets. Leave gaps around evaporators and shelves.
- Check the product, not just the display. Probe food temperatures against the 8°C limit instead of trusting the controller reading, and write them down.
- Keep the record going. If something does go wrong, a log showing what you checked and when is what you will want to hand over.
What it means for your staff
Kitchens are hot places in a normal August, and a red alert makes the working day harder. Here the law is less specific than people expect. The HSE says plainly that "There is no maximum temperature for workplaces", but also that employers must assess the risks to workers, and that heat is a hazard with legal obligations like any other.
In a press release on 19 June, during an earlier heat-health alert, the HSE put it this way: "heat is classed as a hazard and should be treated like other hazards". Its suggestions include flexible working patterns so staff can work at cooler times of the day, free access to drinking water, putting insulation round hot pipes and machinery, and sharing information about the symptoms of heat stress. For a kitchen, that points to prep scheduling, extra water stations, relaxed uniform rules where hygiene allows, and enough breaks for people to cool down.
We have the longer version of the legal position on the sister site, in our UK workplace temperature law guide, so we will not repeat it here.
What to do now
The heat-health season ends on 30 September, but a late warm spell is still possible, and next summer's problems are easiest to fix in autumn.
- Look at every condenser on site and ask whether it has clear space and clean coils.
- Check door seals and closers on walk-ins and reach-in units, and fix anything that does not shut properly.
- Decide who takes food temperatures during a heat alert, how often, and where it is recorded.
- Write a short hot-weather plan for staff, covering water, breaks and prep timing.
- Book commercial refrigeration maintenance for the quiet months, so the first heatwave of next year does not find you with a coil that has not been cleaned since last year.
More on how weather and equipment interact is in our commercial refrigeration news.
