Employers brace for extreme temperatures this week -

Written by

June 22, 2026

Employers brace for extreme temperatures this week

Employers are preparing for a four-day extreme heat warning across much of the UK this week, as temperatures could soar to up to 40°C.

The Met Office has today issued a rare red weather warning – the highest level of alert – for parts of southern England and Wales as temperatures rise to record levels.

The red warning is in place between 9:00am on Wednesday 24 June and 9:00pm on Thursday 25 June.

The Met Office had already put an amber weather warning in place until 11:59pm on Thursday, 25 June, encompassing large swathes of England and Wales. More northerly regions are only under this warning for Wednesday and Thursday.

It said that the current highest temperature on record for June could be broken, which is 35.6°C and was set in 1976.

Deputy chief forecaster Tom Crabtree said: “The combination of heat and humidity will be oppressive and bring impacts across society from public health and infrastructure, to power and water supplies.”

He added that consecutive warm nights that do not drop below 20°C will make it harder for people to recover from the daytime heat, exacerbating these impacts.

The extreme temperatures will lead many employees to question whether it is legally “too hot to work” or to ask for flexible arrangements such as earlier starts.

Heatwaves at work

Help your employees bring their A-game during hot weather

What will new workplace heat guidance man for HR?

There is no legal maximum working temperature in the UK, unlike other countries such as Spain, where the maximum legal indoor working temperature for sedentary work is 27°C and 25°C for light physical work.

Instead, employers are obliged under health and safety legislation to provide a temperature that is “reasonable”.

In May, the Climate Change Committee advised the UK government that a maximum legal temperature range could help employers protect workers’ safety.

Unions have also campaigned for greater regulation around maximum working temperatures, and the TUC introduced workplace inspections for heat safety.

In response to high temperature forecasts, workplace conciliation service Acas made recommendations for employers on how to manage the challenges presented by the heatwave.

“Some workers with certain health conditions or disabilities may be adversely affected by the heat. The hotter weather can also impact public transport, which can disrupt people’s journeys to and from work,” said chief executive Niall Mackenzie.

“Acas has some top tips for employers to help ensure their businesses remain productive during the heatwave while keeping staff happy, too.”

Employers’ legal “duty of care” to their staff includes not only reasonable working temperatures in their place of work, but also when working from home.

At work, this could include providing employees with suitable drinking water or extra breaks so staff can get cold drinks, Acas added. Further measures could include relaxing uniform or dress code requirements.

For vulnerable staff, employers should assess risks and try to reduce or remove these, for example by providing fans, air-cooling units or more frequent breaks.

Risk of accidents

Joshua Hughes, partner and head of the complex injury team at Bolt Burdon Kemp, warned that exceptional temperatures could impair concentration and raise the likelihood of workplace accidents.

“Exceptional temperatures like those we are currently seeing across London and much of England are more than simply uncomfortable – they can create genuinely dangerous working conditions,” he said.

“Despite growing calls for action, whilst there is no upper legal limit for workplace temperatures in the UK, employers still have a clear duty to provide a safe working environment and to properly assess risks posed by extreme heat.”

Bus and train drivers in London could be working in temperatures as high as 40C, he added, alongside warnings of disruption across the transport network as the infrastructure struggles to cope.

“Many of the workplace injury cases we handle arise because employers have failed to take reasonable steps to protect staff from foreseeable risks,” said Hughes.

“As periods of extreme heat become increasingly common in the UK, businesses must ensure that heat-related risks are treated as a serious health and safety issue rather than simply an inconvenience.”

Employee detriment

Patrick Macken, a solicitor at Richard Nelson LLP, said that employees could have recourse to the Employment Rights Act 1996 if they are subject to detriment because they left the workplace due to “serious and imminent danger”.

“While that sounds like a high threshold, the danger doesn’t need to be life-threatening; it includes exposure to harm, injury, or risk. Even the risk of danger is enough to trigger statutory protection,” he said.

Detriment in this context could mean disciplinary action, for example, or anything that “a reasonable employee could perceive as placing them at a disadvantage”.

Macken advised: “While each case is subject to its own merits, employers ought to be mindful of health and safety measures, and avoid knee-jerk decisions to discipline or dismiss employees who take preventative measures, such as adjusting their uniform or opening doors, to stay safe in the heat.”