26th May 2026

Working in Hot Weather

Health and Safety

Introduction

Working in excessive heat is not only uncomfortable but can be dangerous, and in extreme cases, fatal. Hot work, either outdoors or indoors, can lead to an increase in accidents and injuries, and with temperatures across the UK forecast to reach record levels in parts of the UK, we consider the effects this may have on employees at work.

Is it too hot to work?

You may be surprised to learn that there is actually no law for maximum working temperature or prohibition on when it’s too hot to work.

The Workplace (Health, Safety and Welfare) Regulations 1992 state that temperatures within workplaces must be ‘reasonable’. If reasonable comfort cannot be achieved, the Approved Code of Practice expands on this and states that ‘all reasonable steps should be taken to achieve a temperature which is as close as possible to comfortable.’

Firstly, in order to assist in determining what’s reasonable, our first advice would be to provide a suitable wall-mounted thermometer within indoor workplaces to monitor the temperature routinely in order to identify those times when it may become excessive, warranting further action.

It’s a heatwave, what can I do?

The term ‘thermal comfort’ is used to describe a person’s state of mind in terms of whether they feel too hot or too cold.

There’s a range of factors that influence a person’s thermal comfort when at work, which include sources of heat in the workplace, work activities being undertaken and clothing that is being worn. These are all areas that the employer does have some control over and can seek to improve the thermal comfort of employees where necessary.

Key measures include:

Using any readily available natural ventilation, such as opening windows or doors in workplaces.
Relaxing the workplace dress code during particularly hot days (workplace dependent, assuming that work activity risk assessments don’t identify hazards to parts of the body that would usually be covered by standard workwear, such as lower legs, for example.
Using mechanical or forced ventilation, such as air conditioning, localised cooling, and desk or pedestal fans, to increase air movement
Using window blinds (if available) to cut down on the heating effects of the sun
Ensuring there is a readily available supply of drinking water accessible to staff
Reviewing work activities to identify if any possible changes can be made to work away from direct sunlight or sources of radiant heat in the workplace (e.g. heat-producing plant/machinery)
Re-organisation of work so that more of the work will be done in cooler parts of the day
Rotation of workers into tasks and areas that expose them to less heat exposure
Arranging for staff to take regular breaks away from the workplace to cool down more when it’s hot
Working in uncomfortably hot environments is more likely to lead to unsafe working behaviour because people’s ability to make decisions and/or perform manual tasks deteriorates.

By managing thermal comfort, you are likely to improve morale and productivity as well as improve health and safety during this particularly hot spell we are experiencing.

Be aware of heat exhaustion

As the body gets hotter, blood vessels open up. This leads to lower blood pressure and makes the heart work harder to push the blood around the body.

This can cause mild symptoms, such as itchy heat rash and swollen feet. At the same time, sweating leads to the loss of fluids and sweat affects the balance of the body. This, combined with lowered blood pressure, can lead to employees suffering heat exhaustion.

What about working outdoors?

When working outdoors in the UK environment, the effects of the weather can potentially have a serious impact on an employee’s health if the risks have not been considered or properly managed. This impact may be immediate, or it may occur over a long time period.

With temperatures likely rising over the coming years, working outdoors in this heat can lead to dehydration, tiredness, muscle cramps, sunburn, fainting, and – in the most extreme cases – loss of consciousness.

The skin risks from prolonged exposure to the sun are well known. It can clearly cause skin damage, including sunburn, blistering and skin ageing. In the long term can lead to an increased risk of skin cancer. Skin cancer is one of the most common forms of cancer in the UK, with over 50,000 new cases every year.

Employees who work outside in the summer are potentially at risk of developing long-term health issues caused by too much exposure to the sun. Not just skin cancer, but sunstroke. Consequently, given the current extreme weather warning for the UK, employers should have rules and safety measures in place that protect personnel when working outside.

Key recommendations to mitigate this risk include:

Encouraging outdoor workers to wear sunglasses or safety goggles with 100% UV protection
Keeping covered up with long-sleeved, loose-fitting tops and trousers.
Wearing hats/caps, and where safety helmets are needed, these should be fitted with neck flaps.
Promote the regular use of sunscreen
Ensure employees have access to free drinking water
Where possible, reschedule work to cooler times of the day (i.e. before or after mid-day)
Provide more frequent rest breaks and introduce shading to resting areas
Introduce shading in areas where individuals are working
Ensure heads and torsos are kept covered when working in the sun
Consider allowing staff to adopt less formal attire when temperatures rise

What about PPE in hot weather?

There’s no relaxation whatsoever in hot weather – and so please note that Personal Protective Equipment (PPE)/Respiratory Protective Equipment (RPE) must continue to be worn where it’s required – irrespective of the weather conditions. Encourage the removal of personal protective equipment when resting (and it’s appropriate to do so) to help encourage heat loss.

If you require further advice regarding this issue, then please call our health and safety advice line on 0300 3035528, where our team of health and safety advisors will be happy to assist you.