Written by: Rhiannon Wilson, Health & Safety Advisor at CXCS
When temperatures rise, many employers start asking the same question: is there a point where it becomes too hot to work?
The simple answer is that there is no legal maximum workplace temperature. However, that does not mean employers can ignore the impact of hot weather.
Heat can affect concentration, physical performance, decision-making and overall wellbeing. For employees working outdoors, carrying out physical tasks, wearing PPE, working in vehicles, or operating in poorly ventilated areas, the risks can increase quickly.
Employers have a duty to assess and manage workplace risks. During hot weather, this means thinking carefully about how heat could affect staff and what practical steps can be taken to reduce the risk of heat-related illness.
Rhiannon Wilson, Health & Safety Advisor at CXCS, shares guidance on the key risks associated with hot weather at work, along with practical measures employers can take to protect staff and maintain safe working conditions.
Why hot weather should be treated as a workplace risk
Hot weather is not just uncomfortable. In some working environments, it can become a genuine health and safety concern.
Workers may be more likely to experience tiredness, dizziness, headaches, dehydration, reduced concentration or heat stress. In higher-risk situations, heat exhaustion or heatstroke may occur.
The level of risk will depend on the workplace, the type of work being carried out, the people involved and how long workers are exposed to the heat.
For example, a short office-based task in a warm room is very different from outdoor physical work, manual handling, machinery operation, yard work, construction, agricultural work, or any task that involves PPE in direct sun.
This is why employers need to consider the specific circumstances of their own workplace rather than relying on a fixed temperature limit.
What practical steps can employers take?
Employers may need to make temporary adjustments during periods of hot weather. These do not always need to be complicated, but they should be sensible, practical and clearly communicated.
Depending on the workplace, this may include:
- Providing regular access to drinking water
- Encouraging staff to drink little and often
- Allowing more frequent rest breaks
- Providing shade or cooler rest areas
- Improving ventilation where possible
- Moving physically demanding tasks to cooler parts of the day
- Starting earlier to avoid the main heat of the afternoon
- Delaying non-urgent intensive tasks until temperatures reduce
- Rotating tasks where appropriate
- Reviewing lone working arrangements
- Checking whether PPE increases the risk of overheating
- Encouraging sunscreen for outdoor workers
- Allowing suitable loose-fitting clothing where safe to do so
The aim is to reduce the risk while still making sure work is carried out safely.
Outdoor work and heat exposure
Outdoor workers can be particularly affected by hot weather, especially when working in direct sunlight for long periods.
Employers should consider whether work can be planned differently during periods of high heat. This may include changing working patterns, moving work to shaded areas where possible, scheduling the most demanding tasks earlier in the day, or introducing more regular breaks.
It is also important to think about workers using machinery, vehicles or equipment. Heat can affect concentration and reaction times, which may increase the risk of accidents.
For sectors such as agriculture, construction, landscaping, site work, maintenance and yard-based roles, hot weather arrangements should be considered as part of wider risk management.
PPE and hot weather
PPE can make hot weather more challenging.
Protective clothing, masks, gloves, helmets, high-vis clothing or other PPE can reduce the body’s ability to cool down. However, PPE should not simply be removed if it is needed to protect against another risk.
Instead, employers should review how the task is carried out. Could the work be completed at a cooler time of day? Could breaks be increased? Could workers rotate tasks? Is there a cooler rest area available? Can the work be postponed if it is not urgent?
The important point is to consider the full risk picture rather than creating a new risk by removing protection without proper thought.
Heat exhaustion and heatstroke
Managers, supervisors and first aiders should understand the signs of heat-related illness.
Signs of heat exhaustion may include:
- Tiredness
- Dizziness
- Headache
- Feeling sick or being sick
- Excessive sweating
- Muscle cramps
- Fast breathing or heartbeat
- High temperature
- Feeling very thirsty
- Weakness or irritability
Heat exhaustion does not usually need emergency medical help if the person can cool down within a reasonable time. However, heatstroke is far more serious and requires urgent medical attention.
If someone becomes confused, loses consciousness, has a seizure, or remains very unwell after attempts to cool them down, emergency medical help should be sought.
First aiders should be aware of the difference between heat exhaustion and heatstroke, and employees should know who to speak to if they feel unwell.
Communication is key
During hot weather, it is important that any temporary arrangements are clearly communicated to the team.
Workers should know:
- What changes are being made
- When breaks should be taken
- Where drinking water is available
- Where shaded or cooler rest areas are located
- Who to speak to if they feel unwell
- What symptoms they should look out for
- Whether working hours or task priorities have changed
Employees should also feel able to raise concerns if they are struggling with the heat.
Review arrangements as conditions change
Hot weather arrangements should not be a one-off conversation.
If temperatures rise further, work changes, staff are moved to different tasks, or employees report feeling unwell, arrangements may need to be reviewed.
A practical approach is to treat heat like any other workplace hazard: assess the risk, take proportionate action, communicate clearly and review as needed.
Useful guidance
HSE guidance on heat stress in the workplace:
https://www.hse.gov.uk/temperature/employer/heat-stress.htm
HSE guidance on workplace temperature and the law:
https://www.hse.gov.uk/temperature/employer/the-law.htm
NHS guidance on heat exhaustion and heatstroke:
https://www.nhs.uk/conditions/heat-exhaustion-heatstroke/
Need support with hot weather working arrangements?
If you are unsure what hot weather means for your business, or you need support reviewing your workplace arrangements, the CXCS team can help.
We can provide practical health and safety support to help you assess risks, review working practices and take sensible steps to protect your team during periods of high temperatures.