As the UK continues to experience increasingly frequent heatwaves, understanding your rights and obligations in the workplace during extreme heat has never been more important. The UK Health Security Agency (UKHSA) and the Met Office regularly issue heat-health alerts, and with summer temperatures in some parts of England already breaching 30°C and beyond, employers and employees alike need to know where they stand legally.
This article explains the current law on working in hot weather, what employers must do to protect their workforce, and what to do if you believe your employer is failing in their duties.
Is there a maximum legal working temperature in the UK?
No — and this remains one of the most misunderstood aspects of UK employment law. The Workplace (Health, Safety and Welfare) Regulations 1992 require employers to maintain a ‘reasonable’ indoor temperature, but the legislation deliberately stops short of setting a numerical ceiling. The Health and Safety Executive (HSE) takes the view that a single maximum figure cannot apply across all workplaces, a bakery, a foundry, and an open-plan office face very different challenges.
By contrast, minimum indoor temperatures are addressed in guidance: the Approved Code of Practice suggests 16°C as a baseline for sedentary work, or 13°C where work involves physical activity. The absence of an equivalent upper limit is increasingly controversial.
Can I leave work because it’s too hot?
In short: not simply because you feel uncomfortable. There is no automatic right to leave the workplace, or to refuse to work, because it is hot. However, this does not mean employees are without recourse.
The position is more nuanced than a flat ‘no’:
- If you feel unwell: Heat-related illness, such as heat exhaustion or heatstroke, is a genuine medical condition. If you are experiencing symptoms, dizziness, nausea, excessive sweating, rapid heartbeat, or confusion, you may need to take sick leave, just as you would for any other health condition. You should inform your employer and, if symptoms are serious, seek medical attention.
- If there is a serious and imminent risk: Under the Employment Rights Act 1996, employees have the right to leave or refuse to return to a workplace where they reasonably believe there is a serious and imminent danger that they could not reasonably be expected to avert. In extreme circumstances, dangerously high temperatures, particularly for outdoor workers or those in physically demanding roles, could potentially fall within this protection, though this would be a high threshold to meet and would depend heavily on the specific facts.
- If your employer is failing in their duty: If you have raised concerns about working conditions through appropriate channels and your employer has taken no action, this could support a formal grievance or, in more serious cases, a health and safety complaint to the HSE.
What are employers legally required to do?
Even without a defined maximum temperature, employers carry significant legal obligations in hot weather. These arise from several pieces of legislation working together.
The Workplace (Health, Safety and Welfare) Regulations 1992
These Regulations impose a duty on employers to ensure that the temperature in indoor workplaces is ‘reasonable during working hours’. What is ‘reasonable’ will depend on the nature of the work, the physical demands placed on employees, and the environment itself. Employers cannot simply point to an absence of a legal maximum as justification for doing nothing.
The Management of Health and Safety at Work Regulations 1999
The Management of Health and Safety at Work Regulations 1999 require employers to carry out a suitable and sufficient risk assessment covering all significant hazards in the workplace, and temperature is explicitly one of them. This means employers must:
- Actively assess heat-related risks to employee health and safety, not simply wait for complaints to arise
- Identify which workers are most at risk, including those with underlying health conditions, pregnant employees, or those in physically demanding or outdoor roles
- Implement proportionate controls to manage the risk
- Review and update their risk assessments regularly, particularly as weather conditions change
The Health and Safety at Work Act 1974
The overarching duty under this Act requires employers to ensure, so far as is reasonably practicable, the health, safety and welfare of all employees. This includes providing a safe working environment and safe systems of work, both of which are directly relevant when temperatures rise significantly.
Implied duty of trust and confidence
As a matter of general employment law, all employment contracts contain an implied term that employers will not act in a manner that destroys or seriously damages the relationship of trust and confidence. Persistently ignoring reasonable employee concerns about working conditions, including heat, could constitute a breach of this implied term. In the most serious cases, this could give rise to a constructive dismissal claim.
Practical steps employers should take
There is no definitive checklist in law, but the HSE and ACAS guidance identify a range of measures that responsible employers should consider when temperatures are high:
Cooling and ventilation
- Assess whether existing ventilation is adequate, and take steps to improve airflow where it is not
- Provide fans, portable air conditioning units, or other cooling equipment where reasonably practicable
- Install window coverings or blinds to reduce solar heat gain, particularly in south-facing offices
- Create designated cool rest areas where employees can take breaks away from the heat
Hydration
- Provide free access to cool drinking water throughout the working day
- Encourage employees to drink regularly, particularly those engaged in physical work
- Consider providing electrolyte drinks for workers in very hot or strenuous environments
Working hours and flexibility
- Consider adjusting shift patterns so that the most physically demanding work is carried out during cooler parts of the day, for example, early morning or evening
- Introduce additional rest breaks during periods of extreme heat
- Consider allowing remote or hybrid working for office-based roles on the hottest days, where the role permits
Dress code
Employers should consider temporarily relaxing dress codes to allow employees to wear lighter, more breathable clothing. There is no legal right for employees to ignore a dress code, even in hot weather, but equally, employers who rigidly enforce formal wear during a heatwave without taking other steps to manage temperature may find their position difficult to justify if employees suffer heat-related illness.
Health and safety requirements, such as wearing appropriate footwear on a construction site or PPE in a hazardous environment, cannot be set aside on grounds of heat, even if this makes conditions more uncomfortable.
Vulnerable workers
Employers should pay particular attention to workers who may be at heightened risk from heat, including:
- Pregnant employees
- Workers with underlying health conditions, such as cardiovascular or respiratory conditions
- Older workers
- Those taking medication that may affect temperature regulation or hydration
- Outdoor workers, particularly those in construction, agriculture, or landscaping
For these groups, a more tailored risk assessment and enhanced support may be necessary to comply with both health and safety legislation and, where relevant, the Equality Act 2010.
What if my employer fails to act?
If your employer is not taking reasonable steps to manage heat in the workplace, there are a number of routes available to you:
Raise it internally
The first step should normally be to raise your concerns with your line manager, HR department, or, if your workplace has one, a health and safety representative or trade union. Many employers will take action once concerns are raised formally, particularly if you can point to specific symptoms or incidents caused by the heat.
Lodge a formal grievance
If informal approaches do not resolve the issue, you may raise a formal grievance under your employer’s grievance procedure. Keep a record of any concerns raised, the responses you receive, and any incidents or health effects you experience as a result of the working conditions.
Contact ACAS
ACAS provides free, impartial advice to both employers and employees on workplace issues, including health and safety. They can explain your options and help you understand the process before taking further action.
Report to the HSE
If you believe your employer is in serious breach of their health and safety obligations, you can report this to the Health and Safety Executive (HSE). The HSE has powers to investigate, issue improvement or prohibition notices, and in the most serious cases, prosecute employers.
Employment tribunal
In cases where an employer’s failure to provide reasonable working conditions has caused injury, led to a dismissal, or constitutes a breach of contract, legal action may be appropriate. Specialist employment law advice should be sought at the earliest opportunity.
The bigger picture: Heat and the future of workplace law
UK summers are getting hotter. Temperatures exceeded 40°C for the first time on record in 2022, and research from the Autonomy Institute suggests that by the end of this decade, nearly two-thirds of UK workers could face working in temperatures above 35°C during extreme heatwaves. By 2050, that figure could affect over 27 million workers.
Calls for a legal maximum working temperature are growing louder, with the TUC, trade unions, and a number of parliamentarians pressing for change. The Employment Rights Act 2025, while a landmark piece of legislation in many other respects, did not address this gap, leaving the existing ‘reasonable temperature’ standard in place for the foreseeable future.
Employers who take a proactive approach now, investing in cooling infrastructure, updating their heat management policies, and fostering a workplace culture where employees feel empowered to raise health and safety concerns, will be better placed both legally and in terms of staff retention and wellbeing as the climate continues to change.
How Nelsons Can Help
At Nelsons Solicitors, our expert Employment Law team understands the complex balance between employee rights and employer obligations during extreme weather conditions.
Laura Kearsley is a Partner in our expert Employment Law team and can provide specialist advice on all aspects of employment law, including workplace health and safety obligations.
For advice on workers’ rights during hot weather, or any employment law matter, contact our team on 0800 024 1976 or complete our online enquiry form for a prompt.
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