Hot weather can turn an ordinary shift into a health, safety and operational problem surprisingly quickly. A sun-facing office can retain heat into the evening, a busy kitchen can become oppressive, a warehouse may combine physical effort with poor air movement, and a retail team may have little control over doors, glazing or customer footfall. For smaller employers, the answer is not a last-minute box of ice lollies. It is a clear, proportionate heat-health plan that managers can use before and during hot spells.
The central legal point is often misunderstood. There is no single legal maximum workplace temperature in the UK. Instead, employers must manage the actual risks in their workplace, keep indoor temperatures at a comfortable level where reasonably practicable and provide clean, fresh air. The Health and Safety Executive’s workplace-temperature guidance makes clear why a fixed upper limit would not work: heat exposure depends on the work itself, humidity, ventilation, clothing, equipment, individual health and whether people can recover between tasks.
That means your risk assessment, not a thermometer reading alone, should drive your response. This practical plan helps office, retail, hospitality, warehouse and remote-work employers act early, support people who may be more vulnerable, and know when to change how work is done.
Start with a heat risk assessment, not a temperature argument
A heat plan should sit within your normal health and safety arrangements. Ask a manager to review the risk assessment when a hot spell is forecast, when staff raise concerns or when the workplace changes. Involve workers and supervisors: they will know which room gets afternoon sun, which delivery bay has no airflow and which uniform becomes unmanageable during a rush.
The HSE’s workplace temperature checklist is a useful starting point. It directs employers to consider more than air temperature: radiant heat from sunlight, ovens or machinery; humidity; air movement; physical work rate; and clothing or personal protective equipment (PPE). A staff complaint matters too. It may identify a problem that a single reading in a cooler part of the building misses.
Build a simple heat-risk picture for each work area
- Environment: Is the area sun-facing, windowless, crowded, near hot equipment, poorly ventilated or used for cold storage followed by warm work?
- Task: Does it involve lifting, cleaning, cooking, stock movement, driving, queue management, outdoor work or sustained customer service?
- Work pattern: Are people working through the hottest hours, covering absences, working alone or doing overtime after a hot night with little sleep?
- Clothing and PPE: Are staff in formalwear, branded layers, waterproofs, protective footwear, respiratory protection, gloves or other equipment that traps heat?
- People: Could pregnancy, disability, a long-term condition, medication, age, recent illness or limited ability to take breaks make the risk higher?
Record the controls you choose, who owns them and when they will be checked. For a small business, this can be a one-page heat action sheet attached to the existing risk assessment. It should name an on-duty decision-maker, give staff an escalation route and specify what triggers extra measures, task changes or a pause in work.
Use forecasts and warnings to act before the workplace overheats
Do not wait for the hottest day to buy fans or rewrite rotas. Monitor the local forecast several days ahead and ask the duty manager to check the Met Office weather warnings each morning during hot periods. The Met Office distinguishes between a meteorological heatwave and an impact-based Extreme Heat Warning; a heatwave definition alone does not tell you how severe the health or infrastructure effects will be.
In England, employers should also be aware of the UK Health Security Agency’s Weather-Health Alerting System. Heat-Health Alerts focus on likely health impacts, including the cumulative effects of prolonged heat and warm nights. They are England-only, so organisations operating across the UK should combine them with Met Office warnings and local arrangements in Scotland, Wales and Northern Ireland.
Set three practical response levels
Prepare: when a hot spell is forecast, test cooling equipment, order drinking-water supplies if necessary, brief managers, check shade and update staff about dress-code flexibility.
Escalate: when the workplace is becoming uncomfortable or staff report symptoms, introduce additional breaks, move strenuous work, rotate people, open suitable ventilation routes and check higher-risk workers individually.
Protect: if controls are not keeping people safe, stop or postpone the affected task, move work to a cooler location, reduce staffing exposure through rotation or close the affected area temporarily. “Business as usual” is not a control measure when the risk assessment says otherwise.
Hydration: make water easy to access, not just technically available
Under workplace welfare rules, employers must provide an adequate supply of wholesome drinking water that is readily accessible. The HSE’s guidance on drinking water at work also covers suitable drinking vessels where people cannot drink directly from the supply. In a heatwave, think about access in practice. A tap two floors away is not a useful control for a lone receptionist, a warehouse picker on a timed target or a chef in the middle of service.
- Place clearly marked water points close to work areas, including stockrooms, loading areas and staff rest spaces.
- Allow bottles at safe workstations and provide refillable bottles where appropriate.
- Keep water cool where possible, replenish supplies before busy periods and make sure every shift knows where to find it.
- Build short drinks breaks into the rota; workers should not have to choose between hydration and hitting an unrealistic target.
- Brief supervisors to encourage regular drinking rather than waiting until someone feels thirsty.
Avoid treating tea rounds, energy drinks or alcohol after work as substitutes for a hydration plan. The aim is straightforward: make drinking water convenient throughout the shift, especially for people doing physical work or wearing heat-retaining PPE.
Cool the building safely: shade, ventilation and heat sources
Start with low-cost measures that reduce heat entering and building up in the workplace. Close blinds, curtains or external shading before strong sun reaches glazing. Move desks, tills, packing benches and waiting positions away from direct sun and radiant heat where possible. Turn off unused lighting, display equipment and non-essential electrical equipment that adds heat.
Ventilation needs a little judgement. Open windows and doors where safe and useful, but consider security, noise, fumes, pollen, road pollution and whether outdoor air is hotter than the building. Use fans to improve air movement, positioning them so they do not create trip hazards, blow loose materials or make food-preparation conditions unsuitable. The HSE’s workplace welfare guidance identifies shading, local cooling, fans and increased ventilation as possible measures where temperatures are uncomfortably high.
Air conditioning or portable cooling can help, but it is not an excuse to ignore maintenance, layout or workload. Check that units are working before the heat arrives, that filters and drainage are maintained, and that cooled air reaches the people who need it. A portable unit in the manager’s office does not control heat on the shop floor.
Workplace examples
Office: create a cooler desk zone away from sun-facing windows, allow earlier starts, reduce non-essential meetings in hot rooms and offer staff a cooler shared space for focused work. If the building stays hot after closing, review the next morning’s start time rather than assuming everyone has recovered overnight.
Retail: rotate staff away from window displays, entrance positions and hot stockrooms. Keep water behind the till where safe, arrange cover for short breaks and avoid placing staff in direct sun to manage queues. If doors must remain open, consider how this affects indoor heat and security.
Hospitality: separate front-of-house and kitchen risks. Kitchen teams may face heat from cooking equipment, physical pace and protective clothing; front-of-house staff may be exposed to sun in outdoor areas. Schedule prep earlier, rotate hot-station work, provide shaded rest points and review whether outdoor service can be safely reduced at peak heat.
Warehouse: assess roof heat, loading bays, forklifts, manual handling and productivity targets together. Bring forward heavy picking, use task rotation, create a cooled or shaded recovery area and ensure water is available beyond the canteen. Do not let performance targets encourage people to skip breaks.
Change shift timing, workload and breaks
One of the strongest controls available to a small employer is changing when and how work happens. Move physically demanding tasks, deliveries, cleaning, stocktakes and outdoor setup to the cooler part of the day. Avoid scheduling back-to-back heavy tasks in the hottest afternoon period. Where customer demand makes that difficult, use more frequent rotations and provide enough cover for genuine breaks.
Breaks should be restorative, not merely time away from a workstation in the same hot room. Identify a cooler space with seating and drinking water. Give new starters, temporary staff and people returning after sickness particular attention: they may not know how to raise concerns or may feel pressure to prove themselves.
Record any temporary changes to targets, service levels and staffing expectations. This protects staff and gives supervisors permission to make sensible decisions. It also helps avoid an all-too-common problem: a manager announces extra breaks but sets the same output expectation, so workers feel unable to take them.
Uniforms and PPE: relax what you can, never remove essential protection
Hot-weather dress-code changes are often easy and cost nothing. Acas advises that employers are not obliged to relax uniform rules, but may find it sensible to relax requirements such as ties or suits where possible. Its hot-weather workplace advice also highlights flexible working, hydration and support for people whose health may be affected by heat.
Allow lightweight, loose-fitting and light-coloured clothing where it does not compromise safety, hygiene, brand needs or dignity. Consider alternatives to heavy branded layers, and give staff clear guidance so managers apply the policy consistently.
PPE is different. Do not tell a worker to remove required protection simply because it is hot. PPE can increase heat strain, so change the system around it: reduce exposure time, improve ventilation, provide cool recovery breaks, rotate tasks and review whether the equipment is correctly specified and fitted. The joint UKHSA and HSE guidance on PPE and heat stress stresses the importance of managing heat risk, including ventilation and reasonable workplace temperatures.
Protect vulnerable staff through conversation and adjustments
Heat affects people differently. The NHS identifies higher risk for older people and for people who are pregnant or have serious long-term conditions, including heart, breathing, kidney and diabetes-related conditions. Medication can also affect how a person copes with heat. Employers should not demand medical details in a group briefing or make assumptions about who can cope. Instead, invite confidential conversations early and ask what would help the person work safely.
Possible adjustments include a cooler work location, changed hours, home working where suitable, more frequent breaks, a temporary reduction in strenuous tasks, a fan or portable cooling unit, or permission to wear different clothing. Where disability is involved, consider your duties to make reasonable adjustments. Acas specifically advises employers to assess risks and discuss what is needed with workers whose health condition or disability may be adversely affected by hot weather.
Pregnant workers and people with recently declared health conditions may already have individual risk assessments. Review them when conditions change. HSE guidance on occupational health also points employers to review risk assessments when a worker declares a condition or returns after sickness absence.
Remote workers and lone workers need an active plan too
Home working does not remove an employer’s health and safety responsibilities. The HSE says employers have the same responsibilities for home workers as for other workers, although risks will often be low and the response straightforward. Ask remote staff whether they have a safe, workable and reasonably cool place to work during the hot spell. Someone in a top-floor flat, a room with fixed glazing or a home without safe ventilation may need flexibility rather than a reminder to “stay hydrated”.
Offer earlier or later hours, temporary access to a cooler workplace or agreed alternative location where appropriate, sensible workload adjustments and permission to take short cooling breaks. Make clear how to report feeling unwell and avoid scheduling long video meetings in the hottest part of the day.
Lone workers deserve specific attention. A heat-related illness can become more serious when no one is nearby to spot confusion, faintness or deteriorating symptoms. HSE’s lone-working guidance says lone workers face the same hazards as others but may face greater harm because help is not immediately available. Use planned check-ins, confirm a working phone and escalation procedure, and reconsider whether isolated hot work, driving, roof-space visits or manual handling should proceed alone.
Train managers to recognise symptoms and respond quickly
Every supervisor should know the signs of heat exhaustion: tiredness, dizziness, headache, nausea, cramps, excessive sweating, pale clammy skin, thirst and irritability can all be warning signs. The NHS advises moving the person to a cool place, removing unnecessary clothing, giving fluids and cooling their skin. Stay with them and seek urgent help if they are not improving.
Heatstroke is an emergency. Warning signs include a very high temperature, hot skin without sweating, fast breathing or heartbeat, confusion, seizures or loss of consciousness. Follow the NHS guidance on heat exhaustion and heatstroke: call 999 for signs of heatstroke or where someone remains unwell after 30 minutes of cooling and drinking fluids. Do not leave a person who is seriously unwell to “sleep it off”, and do not expect them to travel home alone.
Make the plan a normal part of summer operations
A good heatwave plan is brief, specific and used. Before summer, review the building, order supplies, agree dress-code options, identify cool spaces and brief managers. When a warning arrives, revisit the risk assessment, communicate the day’s arrangements and listen to staff. After the event, ask what failed: was water too far away, did the hottest team get no cover, did cooling equipment arrive too late, or were remote workers forgotten?
For UK small businesses, the objective is not to find a magic maximum temperature or create needless paperwork. It is to recognise the particular conditions your people face and reduce the risk in a practical way. Put your one-page heat-health plan in place now, share it with every manager and give staff confidence that speaking up will lead to action.
