Do UK employers have to follow specific rules for hot workplaces when the temperature rises? Yes. UK law requires you to keep working conditions reasonable in hot weather, assess heat risks, and reduce them. There is no legal maximum temperature, but you still have clear duties under health and safety law.
In the UK, the Workplace (Health, Safety and Welfare) Regulations 1992 require a reasonable temperature in workplaces, judged by thermal comfort not a fixed number. The Health and Safety Executive (HSE) says you must assess heat risks and act, especially for strenuous work or vulnerable staff. We explain the rules, the practical steps, and when to adjust hours, pace, clothing, and breaks. If you need hands-on help building a hot weather policy, speak to our team via our HR Services page at Specialised HR.
What does UK law actually require when it gets hot?
You must provide a reasonable temperature, complete a risk assessment, and take proportionate measures. The law focuses on risk control, not a single cut-off temperature.
Your core duties include:
- Health and Safety at Work etc Act 1974, Section 2. You must ensure, so far as is reasonably practicable, the health, safety and welfare of employees legislation.gov.uk.
- Workplace (Health, Safety and Welfare) Regulations 1992, Regulation 7. You must maintain a reasonable temperature, taking account of work activity and environmental conditions legislation.gov.uk.
- Management of Health and Safety at Work Regulations 1999. You must risk assess heat stress and put controls in place legislation.gov.uk.
- Equality Act 2010. You must make reasonable adjustments where heat exacerbates a disability or impacts pregnancy legislation.gov.uk.
In our experience supporting ethical employers, the most effective actions are simple. Provide cool water, schedule heavy tasks earlier, and give more frequent breaks. Document these controls in your risk assessment and communicate them clearly.
Is there a legal maximum workplace temperature in the UK?
No. There is no legal maximum workplace temperature in UK law. The duty is to keep conditions reasonable and manage the risk of heat stress.
The HSE confirms there is no maximum temperature limit, and thermal comfort is the test. Workload, humidity, clothing, ventilation, and radiant heat all matter HSE thermal comfort. Minimum guideline temperatures do exist for comfort at 16°C for sedentary work and 13°C for physical work, but these are not legal limits. They are a guide for reasonable conditions HSE. It is easy to assume you only need to act when a thermometer passes a set point. The reality is broader. You must monitor conditions and reduce risk when people start to feel unwell or performance drops.
Industry perspective: Trade unions including the Trades Union Congress have called for a legal maximum of 30°C in most workplaces, and 27°C for strenuous work, with more breaks and common-sense controls TUC. This proposal is not law, but it shows rising expectations for employer action.
What temperature should trigger a heat risk assessment?
You should assess risk when indoor or outdoor conditions make heat stress plausible, not at a single temperature. Watch for symptoms, high humidity, radiant heat, and heavy work.
The HSE advises a risk assessment whenever heat could cause harm. That includes hot weather, high-radiant environments, kitchens, factories, construction sites, warehouses, and greenhouses HSE heat stress. Assess:
- Environmental factors. Air temperature, humidity, radiant heat from machinery or sun, and air movement.
- Work factors. Task load, pace, required protective clothing, and shift length.
- Individual factors. Acclimatisation, fitness, medications, pregnancy, and existing health issues.
The UK recorded a new temperature record of 40.3°C on 19 July 2022, confirming that extreme heat is now a real planning scenario Met Office.
What practical steps should employers take when temperatures climb?
Start with simple, low-cost controls, then escalate as needed. Focus on ventilation, hydration, breaks, scheduling, and clothing.
Here is a practical sequence you can adapt:
1) Improve airflow. Open vents and windows where safe, use fans where appropriate, and service HVAC. Target hotspots first.
2) Provide cool drinking water. Make it easy to access, remind teams to drink often, and allow water bottles at workstations.
3) Adjust work pattern. Move heavy tasks to cooler times, rotate staff on strenuous roles, and shorten exposure periods.
4) Increase breaks. Add short, frequent rest breaks in a cooler space. Encourage early reporting of symptoms.
5) Relax clothing rules. Use lighter uniforms, remove ties or jackets, and allow brimmed hats for outdoor workers.
6) Reduce heat sources. Insulate hot surfaces, shade windows, and switch off idle equipment that throws off heat.
7) Review PPE. Select breathable options where standards allow, and allow extra breaks if PPE adds heat load.
8) Brief managers. Train supervisors to spot heat exhaustion and to act quickly if anyone becomes unwell.
You can find helpful templates and policy support through our Explore Our HR Services page. If this feels overwhelming, our team can create a tailored hot weather policy for your organisation.
How should we protect outdoor, kitchen, factory and office teams differently?
Apply the same principles, but tailor controls to the environment. Outdoor and high-heat roles need more frequent breaks and shade.
- Outdoor and site-based work. Provide shade, sunscreen, brimmed hats, and cool water. Stagger shifts, avoid midday peaks, and use buddy systems to spot symptoms early.
- Kitchens and food production. Improve extraction, rotate hot station duties, and review uniform fabric. Review hydration rules against food safety requirements.
- Warehouses and factories. Map hotspots around machinery, add local fans or spot cooling, and reduce manual handling where possible.
- Offices and call centres. Offer flexible hours or temporary homeworking if buildings overheat. Relax dress codes and reduce non-essential in-person meetings in peak heat.
What this means for charities and social enterprises:
Volunteers and part-time staff need the same protections as employees. Clear briefings and simple signage can make a big difference to safety and morale.
What are the signs of heat exhaustion and heatstroke that managers should know?
Heat exhaustion develops gradually, while heatstroke is a medical emergency. Quick recognition protects people and prevents serious incidents.
Look for symptoms such as heavy sweating, dizziness, headache, muscle cramps, nausea, and fast breathing. If symptoms appear, stop work, move to a cool place, and rehydrate. If confusion, very high temperature, or loss of consciousness occurs, call 999. The NHS provides clear guidance on symptoms and first aid for heat exhaustion and heatstroke NHS. Managers should practise these steps and keep first aiders briefed before every heatwave.
Do pregnant or disabled workers need specific adjustments in hot weather?
Yes. You may need reasonable adjustments for pregnancy and disability. Heat can worsen certain conditions and increase risks.
Under the Equality Act 2010, you must consider how heat interacts with specific health needs. The HSE also expects additional risk assessment for pregnant workers HSE pregnant workers. Practical adjustments include:
- More frequent rest breaks and access to cooler rooms.
- Temporary changes to duties that reduce exertion.
- Flexible hours or remote work during peak heat.
- Alternative uniforms or fabrics that improve comfort.
We can help you document these adjustments and keep them proportionate and fair. If you are a charity or not-for-profit, our dedicated support explains your obligations in plain English.
Can employees refuse to work if it is too hot?
Employees may stop work if they reasonably believe there is serious and imminent danger. This is a high bar and depends on context.
Section 44 of the Employment Rights Act 1996 protects employees from detriment if they leave or refuse to return to a workplace they reasonably believe is dangerous legislation.gov.uk. Section 100 covers automatic unfair dismissal for the same scenarios legislation.gov.uk. Most hot weather disputes can be avoided with clear risk assessments and simple controls. ACAS adds practical advice on discussing heat concerns and agreeing adjustments early ACAS hot weather.
What should a hot weather policy include to stay compliant and fair?
Your policy should set out triggers, controls, roles, and communication steps. Keep it short, clear, and aligned with your risk assessment.
Checklist you can adapt today:
- Purpose and scope. State that the aim is to manage heat risk for all workers and volunteers.
- Legal basis. Reference the 1974 Act, the 1992 Workplace Regulations, and your duty to risk assess.
- Triggers. Use combinations such as heat-health alerts, indoor temperature trends, and specific task risks.
- Controls. List measures from ventilation and hydration to break schedules and clothing rules.
- Vulnerable staff. Explain how to request adjustments and who will review them.
- Communication. Confirm who briefs teams, when updates go out, and how to report concerns.
- Review cycle. Commit to an annual pre-summer review, plus a post-heatwave debrief.
If you need a bespoke policy that fits your sector and sites, our team can help you draft and implement it. You can Book a Free Consultation to get started.
How do we plan for heatwaves across the summer months?
Create a simple timeline. Prepare before summer, activate controls during alerts, and review after each heat event.
Timeline expectation:
- Spring readiness: Review last year’s lessons, service ventilation, test water stations, and refresh manager training on heat first aid.
- When a Heat Health Alert is issued: UK Health Security Agency and the Met Office issue alerts for England. Use these as prompts to brief teams and activate controls Gov.uk heat alerts.
- During a heatwave: Increase supervision, shorten exposure periods, and monitor indoor hotspots twice daily. Encourage early reporting of symptoms.
- After the event: Hold a short debrief. Capture what worked, address any incidents, and update your risk assessment and policy.
Quick recap: You prepare early, act fast during alerts, and improve after each event. This cycle keeps your response sharp and trusted.
How do we measure and monitor thermal comfort in practice?
Use a mix of observation and measurement. Track temperature and humidity, then listen to staff feedback.
The HSE advises a practical approach. Combine simple tools, such as digital thermometers and hygrometers, with worker feedback and manager walkarounds HSE thermal comfort. In higher risk environments, consider Wet Bulb Globe Temperature meters to capture radiant heat. Set up a basic log:
- Twice-daily readings in known hotspots and cooler control areas.
- Notes on workload and PPE use at the time of readings.
- Any symptoms reported or breaks added that day.
Data helps you decide when to rotate tasks, add breaks, or change shift patterns. It also shows due diligence if you need to evidence decisions later.
What common mistakes do employers make in hot weather?
Most mistakes come from waiting too long to act or relying on a single number. A few traps are easy to avoid.
Common mistakes box:
- Chasing a magic temperature. There is no legal maximum. Focus on risk, symptoms, and task type instead.
- Ignoring humidity and radiant heat. These matter as much as air temperature for thermal stress.
- Applying a single rule to all roles. Outdoor, kitchen, and office teams need different controls.
- Forgetting vulnerable workers. Pregnancy, some medications, and long-term conditions increase risk.
- Poor communication. If people do not know the plan, they cannot follow it. Brief early and often.
How have values-led employers handled heat risk well?
Successful organisations act early, communicate clearly, and review often. The culture matters as much as the plan.
One ethical retailer we supported moved warehouse picking to early mornings on heat-alert days, added water stations to every aisle, and relaxed uniform rules sensibly. Complaints dropped, and shift fulfilment remained stable through the summer. A small charity restructured its event volunteer plans around shade and shorter shifts. It reported smoother events and fewer incidents. The path is straightforward. Small, practical changes make a big difference.
ACAS recommends involving staff in decisions about heat controls. It improves buy-in and helps you spot practical barriers ACAS hot weather.
Where can you find authoritative guidance on hot workplaces?
Rely on the HSE for legal and technical guidance, and ACAS for practical people management. Use UKHSA and the Met Office for alerts.
Start here:
- Health and Safety Executive. Thermal comfort, heat stress controls, and risk assessment templates HSE heat stress.
- Advisory, Conciliation and Arbitration Service. Managing hot weather conversations and adjustments ACAS.
- UK Health Security Agency and Met Office. Heat Health Alerts and seasonal advice Gov.uk.
What this means for your organisation: Clear, trusted sources reduce confusion. Build your policy around these, then tailor controls to your operations.
Expert insight: We recommend nominating a heat lead for each site. Give them a simple checklist and the authority to add breaks or pause tasks when needed.
If you would like practical help to set the policy, train your managers, and communicate with your teams, our flexible HR consultancy is designed for values-led organisations. Explore Our HR Services to see how we work, or Book a Free Consultation for tailored advice.
Ready to protect your people and keep operations running smoothly this summer?
- Explore practical support on our HR Services page: https://www.specialisedhr.co.uk/hr-services
- Speak to a consultant via Book a Free Consultation: https://www.specialisedhr.co.uk/book-a-call/
- If you work in renewable and green energy, see our specialist support: https://www.specialisedhr.co.uk/hr-support-services-for-green-sustainable-energy-organisations
FREQUENTLY ASKED QUESTIONS
What are the basic UK rules for working in hot weather?
The core rule is to keep workplace conditions reasonable and manage heat risks. UK law requires you to assess heat hazards and take sensible controls.
In practice, you should:
- Review temperature, humidity, workload, clothing and PPE.
- Provide water, ventilation and rest breaks.
- Adjust shifts or duties during heat alerts.
The Health and Safety Executive explains your legal duties on thermal comfort and heat stress so you can build a simple, effective plan.
Why is there no legal maximum temperature for UK workplaces?
The law focuses on risk and comfort rather than a single number. The Workplace Regulations 1992 require a reasonable temperature, but different roles and environments demand different controls.
For example:
- A kitchen or foundry needs stronger measures than an office at the same reading.
- Humidity, radiant heat and workload change the risk.
The HSE’s approach lets you tailor controls to keep people safe across many settings.
What happens if we ignore heat risks at work?
Ignoring heat risk can harm staff and expose you to legal and reputational damage.
Potential consequences include:
- Heat exhaustion, fainting or heatstroke incidents.
- Increased errors and accidents as concentration drops.
- Breaches of health and safety duties if you do not assess and control risk.
Prevention is straightforward. Small steps like water, breaks and scheduling reduce risk and show clear due diligence.
What are the signs of heat exhaustion I should brief my team on?
The main signs are heavy sweating, dizziness, headache, cramps and nausea. Brief teams to stop work, move to a cool place, and rehydrate if symptoms appear.
For clarity:
- Heat exhaustion is serious but usually recoverable with rest and fluids.
- Heatstroke is a medical emergency with confusion or collapse.
Call 999. Managers and first aiders should refresh training before hot spells and review NHS guidance to stay confident.
How can I reduce heat risks in a warehouse or factory?
A simple plan covering airflow, hydration and workload works best. Start by mapping hotspots around machinery and sun-exposed areas.
Then:
- Add local fans or spot cooling and service extraction.
- Rotate strenuous tasks and introduce short, frequent breaks.
- Relax clothing rules where safe and review PPE options.
Keep a daily log of conditions and issues so you can adjust quickly and evidence decisions if needed.
How do we handle heat risk for outdoor teams on peak days?
Plan around shade, fluids and time of day to reduce exposure.
For outdoor work:
- Avoid midday peaks, start earlier, and rotate crews more often.
- Provide shaded rest areas, cool water and brimmed hats or neck shades.
- Use a buddy system and brief on symptoms of heat stress.
Check local Heat Health Alerts to trigger these steps and keep supervisors empowered to pause tasks if conditions worsen.
What should a hot weather policy include for offices and call centres?
Your policy should set triggers, controls and communication steps tailored to office work.
Useful inclusions are:
- Relaxed dress code and permission for water at desks.
- Temporary homeworking or flexible hours in heatwaves.
- Reduced in-person meetings in overheated rooms.
Add a short checklist for managers to review room temperatures, ventilation and staff comfort twice daily during alerts.
Can an employee legally refuse to work if it feels too hot?
Employees may refuse if they reasonably believe there is serious and imminent danger. This depends on the context and the controls you have in place.
To avoid disputes: – Keep your risk assessment current and visible.
- Offer practical adjustments like breaks and cooler duties.
- Discuss concerns early and document actions.
Clear communication and swift, sensible measures usually prevent issues escalating to formal refusal.
How do we make reasonable adjustments for pregnancy or disability in heat?
Focus on rest, reduced exertion and cooler environments to keep people safe.
Adjustments might include:
- Extra breaks and access to cooler rooms.
- Temporary task changes or reduced pace.
- Flexible hours or homeworking on peak days.
Review adjustments regularly and involve the employee in decisions. This builds trust and ensures the measures remain practical and proportionate.
When should we activate our heat plan during summer?
Use heat alerts and your own monitoring to trigger action early.
A simple approach is:
- Spring: service ventilation and brief managers.
- Alert issued: brief teams, relax dress code, stock water.
- Peak days: add breaks, rotate tasks and monitor conditions twice daily.
- After: hold a short debrief and update your plan. This rhythm keeps your response consistent and credible throughout the season.
Related Resource
See how we help values-led organisations with policies, training and practical HR support, including hot weather planning.
Speak to a qualified HR consultant about heat risk, policies and manager training tailored to your organisation.
If you operate in renewable or green energy, learn how we support field teams and site operations through seasonal risks.
Further Reading
Detailed advice from the HSE on managing thermal comfort, including factors beyond temperature.
Need some help with your organisation?
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