Although the UK has no legal maximum workplace temperature, employers are still subject to extensive health and safety obligations that apply throughout periods of extreme weather.
Employers’ Legal Duties During Extreme Heat
The starting point is the Health and Safety at Work etc. Act 1974, which requires employers to take reasonably practicable steps to protect the health, safety and welfare of employees. Those duties are supplemented by the Management of Health and Safety at Work Regulations 1999, which require employers to assess workplace risks and implement appropriate control measures where hazards are identified.
The Workplace (Health, Safety and Welfare) Regulations 1992 also require workplace temperatures to be “reasonable”. However, the legislation deliberately avoids specifying a maximum temperature, leaving employers to assess what is reasonable in the context of the work being undertaken and the environment in which it is carried out.
As a result, the legal question is not whether a workplace has exceeded a particular temperature threshold. The issue is whether an employer has adequately identified and managed the risks created by the conditions.
That assessment will vary significantly between workplaces. An air-conditioned office may present very different risks from a warehouse, construction site, manufacturing facility or outdoor workplace exposed to direct sunlight throughout the day.
Particular attention may be needed for employees who are more vulnerable to heat-related illness, including:
- Pregnant employees.
- Older workers.
- Employees with cardiovascular or respiratory conditions.
- Workers taking medication that affects temperature regulation.
- Employees carrying out physically demanding tasks.
- Lone workers who may have limited access to assistance if they become unwell.
Employers also need to consider their obligations under the Equality Act 2010. Where an employee has a disability that makes them more susceptible to the effects of heat, there may be a duty to make reasonable adjustments. Depending on the circumstances, this could include changes to working arrangements, altered hours, additional rest breaks or temporary home working arrangements.
Employers should also remember that heat-related illnesses occurring in the workplace may trigger reporting and investigation obligations where serious incidents arise.
The Health and Safety Executive has not issued specific temperature limits for workplaces. Instead, its guidance focuses on risk management, encouraging employers to consider factors such as air movement, humidity, access to drinking water, workload and the physical condition of employees.
Can Employees Refuse To Work During A Heatwave?
One of the most common questions during periods of extreme weather is whether employees can simply refuse to attend work because temperatures are uncomfortably high.
In most cases, the answer is no.
The fact that a workplace is hot does not automatically give employees the right to leave work, refuse duties or stay at home. The absence of a legal maximum workplace temperature means there is no fixed point at which work becomes unlawful.
That said, employees do have important legal protections where health and safety concerns arise.
Under Section 44 of the Employment Rights Act 1996, employees are protected from suffering detriment if they leave or refuse to return to a workplace in circumstances where they reasonably believe there is a serious and imminent danger that they cannot reasonably be expected to avoid.
The key issue is not the temperature itself but whether the employee’s belief is reasonable in the circumstances. In practice, that is likely to be a high threshold in most workplaces.
An employee working in a modern, air-conditioned office is unlikely to establish serious and imminent danger simply because external temperatures are unusually high. However, the position may be different where working conditions create a genuine health and safety risk.
Examples could include:
- Workplaces with inadequate ventilation during extreme temperatures.
- Outdoor work involving prolonged exposure to direct sunlight.
- Physically demanding roles carried out in high heat conditions.
- Situations where drinking water, shade or rest facilities are not readily available.
- Employees with known medical vulnerabilities who face increased health risks from heat exposure.
Each situation will depend on its specific facts. Tribunals generally look at the overall circumstances rather than applying a simple temperature-based test.
Employers that investigate and respond promptly to heat-related concerns are likely to be in a stronger position if complaints later arise.
The current heatwave also presents practical attendance challenges beyond workplace temperatures. Transport disruption, school closures and health concerns affecting family members may all have implications for workforce management. A flexible and proportionate approach can often reduce the likelihood of employee relations issues developing during periods of extreme weather.
While the legal threshold for refusing work remains relatively high, employers should not assume that extreme heat falls outside the scope of workplace health and safety law. The greater risk often lies in failing to respond appropriately when concerns are raised.
Practical Steps Employers Should Be Taking During The Heatwave
For most employers, the priority is not legal interpretation but practical risk management.
The current red heat warning is expected to affect large parts of England and Wales, with temperatures reaching levels rarely experienced in the UK. Organisations that take sensible precautions now are likely to reduce both health and safety risks and operational disruption.
The appropriate response will vary according to the workplace and the nature of the work being undertaken. However, there are several practical measures that employers should consider during periods of extreme heat.
- Review workplace risk assessments to identify any heat-related hazards.
- Ensure employees have easy access to drinking water throughout the working day.
- Allow more frequent rest breaks where working conditions are particularly demanding.
- Relax dress codes where this can be done safely and appropriately.
- Use fans, air conditioning or other cooling measures where available.
- Adjust working hours to avoid the hottest parts of the day, particularly for outdoor workers.
- Reduce physically demanding tasks where heat exposure is likely to increase risks.
- Check on lone workers and employees working in isolated locations.
- Review travel requirements where transport disruption is anticipated.
- Remind managers how to recognise signs of heat exhaustion and heatstroke.
Communication is another important factor. Employees should know who to contact if they experience heat-related symptoms or have concerns about their working conditions. Clear communication can help address issues before they develop into health and safety incidents or employee relations problems.
Managers should also be alert to the impact of high overnight temperatures. The Met Office has warned of so-called “tropical nights” in some areas, where temperatures remain above 20°C overnight. Employees who have struggled to sleep may experience fatigue, reduced concentration and lower productivity during the working day.
Hybrid and home working arrangements may also require consideration. While some employees may prefer to work from home, others may have access to cooler and more comfortable conditions in the workplace. Assumptions should therefore be avoided, with decisions based on individual circumstances and operational requirements.
Extreme heat remains relatively unusual in the UK, but it is becoming a more frequent workplace challenge. Employers do not need to eliminate every inconvenience associated with hot weather. They do, however, need to take reasonable steps to protect employees from foreseeable risks and respond appropriately when conditions become more severe.
Author
Gill Laing is a qualified Legal Researcher & Analyst with niche specialisms in Law, Tax, Human Resources, Immigration & Employment Law.
Gill is a Multiple Business Owner and the Managing Director of Prof Services - a Marketing & Content Agency for the Professional Services Sector.
