"Too hot to work": Lawyer explains workers’ rights during a heatwave as record for hottest May day broken again

The record for the hottest May day has been broken again, with provisional temperatures surpassing 35C in London, the Met Office has said. The unseasonably hot temperatures are making even the simplest of tasks that little bit harder - especially off the back of a poor night’s sleep.

In a post on X, the Met Office said: “Today is now the hottest day in May on record for both England and Wales with Kew Gardens provisionally reaching 35.1°C and Cardiff Bute Park reaching 32.9°C.”

The weather service said Heathrow had also provisionally recorded 35C, adding: “Until yesterday the highest temperature in May was 32.8C, but we’ve now exceeded that record on consecutive days by a full two degrees Celsius.”

The UK Health Security Agency (UKHSA) said amber heat-health alerts for the South West, South East, London, East and West Midlands and the East of England will remain in place until 5pm on Thursday, with yellow heat-health alerts for the North West and North East.

But can it ever be ‘too hot to work’ and what are employers’ responsibilities when it comes to working through a heatwave? We spoke to employment law experts at Weightmans who explained employee rights while working in high temperatures.

Working during a heatwave - legal guidelines

Unfortunately, there are no specific laws that allow workers to stop working if it becomes too hot. However, James Muller, Principal Associate in Weightmans’ Health & Safety Team, emphasises that under UK employment law, every employer has a duty of care to ensure a safe working environment and protect the health and welfare of their employees.

"If an employer fails to meet this responsibility, they would face enforcement action (including potential criminal prosecution) from the Health and Safety Executive or Local Authority. Employees might also be able to claim personal injury compensation if they become ill or injured as a result," he adds.

Muller explains that employers must take all "reasonably practicable" measures to ensure the health and welfare of their employees. This means they must provide a safe environment where staff are not at risk of heat-related illnesses.

"Employers must also consider those with existing health conditions that could be more severely affected by high temperatures, such as medically vulnerable individuals or pregnant employees," he continues.

During a heatwave, it is recommended that employers seek to be as flexible as possible, taking into consideration their employees’ well-being, any health conditions and the needs of the business. These issues can sometimes conflict with each other, but generally speaking employers could consider short-term adjustments to working practices such as allowing flexible hours so employees can avoid peak heat times, encouraging remote working, or even shortening the working day if that is operationally viable.

Providing more frequent breaks, particularly for those in physical jobs, can prevent heat-related illnesses and still keep productivity high. The impact of heat on employees can vary significantly depending on their working environment. Employees in physically demanding roles face higher risks during heatwaves.

Employers should offer hydration stations, shaded rest areas, and breathable protective gear. Rotating tasks to limit heat exposure is also beneficial. For office environments without air conditioning, optimising ventilation, designating cooler break areas, and allowing lighter clothing can help.

Encouraging work-from-home options can also alleviate discomfort. For those working from home without air conditioning, providing fans or portable units and offering utility stipends are effective support measures.

The Health and Safety at Work Act 1974 and the Workplace (Health, Safety, and Welfare) Regulations of 1992 (regulations 6 and 7) detail that employers must ensure a healthy work environment by providing sufficient quantities of fresh or purified air, especially during a heatwave. Regularly maintaining air conditioning systems and replacing filters is crucial. Enhancing ventilation through fans and open windows, adding indoor plants to improve air quality, and using dehumidifiers to control humidity levels are important steps.

Workplace dress code during a heatwave

An employer might adjust dress code rules for warmer weather if it's suitable. However, they can still require certain appearance standards, especially for roles involving customer interaction and to ensure health and safety. Ignoring dress code policies could lead to disciplinary measures. Employees would be advised to check with their employer if there is any uncertainty or perceived ambiguity within their policies rather than simply assuming that shorts and flip flops will be acceptable when the mercury rises.

When the working environment is uncomfortably warm, employers should consider:

• Using fans or air conditioning (including mobile air conditioning units) if available / possible
• Providing cool water and encouraging employees to stay hydrated
• Adjusting dress code requirements, if suitable

If employees have additional ideas to improve comfort during warm weather, they should share them with their employer, who should take reasonable suggestions into account.

Legal maximum temperature for workplaces

Employees cannot decide to leave the workplace if it gets too hot, unless unless they feel unwell and need to take sick leave, says James. The Workplace (Health, Safety and Welfare) Regulations 1992 does require employers to ensure a "reasonable" working temperature in the office however. It is an employer's responsibility to determine what constitutes reasonable comfort in specific situations. Employers should also consider this in the context of any employees who have health conditions or are pregnant. As with many scenarios, discussing matters and agreeing a reasonable way forward is usually the best approach.

Employees can be sent home if it gets too hot, though there’s no legal maximum temperature for workplaces. The Health and Safety Executive requires employers to ensure a reasonable and safe working environment. If extreme heat poses a risk to health and safety, employers must take appropriate actions, which could include sending employees home.

If employees are able and equipped to work from home (or another workplace), that should be straightforward. If an employee is not able to work in an alternative cooler location, in many cases, they will still be entitled to be paid as they are ready and willing to work, but it will depend on the exact circumstances, the terms of the employment contract and the employer’s policies.