Summary: No legal maximum temperature doesn’t mean no legal responsibility. When a red alert is issued, employers need to be moving on risk assessments, reasonable adjustments and flexible working.
With the Met Office issuing a red heat health alert for six regions of England this week and temperatures forecast to exceed 37°C (hotter than Spain currently) it can be hard to stay cool-headed at work.
The UK Health Security Agency has described the risk as applying to “even the healthy population”. This isn’t a three-day productivity blip or distraction. It’s a genuine workplace health and safety event, and HR needs a plan.
No maximum temperature doesn’t mean no duty
The first question employees will ask is whether it’s too hot to work.
The honest answer is there’s no legal maximum working temperature in the UK. Employees don’t have an automatic right to down tools because it’s warm.
The Health and Safety Executive set a minimum workplace temperature of 16°C (13°C for physically demanding work) but clearly states there is “no meaningful upper limit”.
What employers do have, however, is a legal duty of care.
That means keeping temperatures at a comfortable level, with clean fresh air, and carrying out risk assessments before assigning work. Particularly anything physical or outdoors, and take reasonable steps to prevent foreseeable harm.
Heat should be treated as a workplace hazard in the same way as any other health and safety risk.
The practical upshot is that HR and line managers shouldn’t wait for employees to raise concerns, but get ahead of it. Review and update risk assessments, paying particular attention where work is physically demanding, undertaken outdoors or involves vulnerable employees.
Heat should be treated as a workplace hazard in the same way as any other health and safety risk
Practical steps: what the HSE recommends
The HSE guidance is clear on what employers can do to protect indoor workers: provide fans or air conditioning; improve ventilation and allow windows to open; use blinds or reflective film to block direct sunlight; move workstations away from heat sources; and supply free cold drinking water.
It’s worth noting that during a red alert event like this current heatwave, these are baseline requirements.
For outdoor workers, the risks are higher and the responsibilities more acute. Reschedule physically demanding work to cooler parts of the day. Provide shaded rest areas. Increase the frequency of breaks.
Employers should also think about potential personal injury claims if employees suffer heat-related illness and appropriate precautions were not taken.
Offer drinking water, rest breaks and staggered hours where you can. And ensure workers can recognise the symptoms of heat stress – headache, dizziness, nausea, rapid heartbeat – so any concerns can be escalated.
Flexible working and getting to work
Extreme heat affects more than comfort at a desk, it affects the journey, especially for employees dependent on public transport. Trains slow down, surfaces become unsafe and commuting in 37°C heat can leave employees arriving already depleted, if at all.
Where possible, allow employees to adjust their start and finish times to avoid peak heat in the middle of the day.
Consider whether meetings that require travel can move online. Rethink productivity: this isn’t so much about avoiding work, rather it’s about directing energy where it matters and removing unnecessary exposure to conditions that carry genuine health risk.
For roles where remote working is an option, a temporary, short-term shift to home working is just good sense.
Vulnerable employees
HR teams should be particularly mindful of their duties under the Equality Act 2010.
For example, are some of your employees may be at greater risk from the impact of the heat because of pre-existing medical conditions.
The heat may exacerbate symptoms and make it more difficult for individuals to carry out their role safely. In these circumstances employers may need to consider reasonable adjustments under the Equality Act 2010.
Also, employees who are pregnant may also need a little extra support in the circumstances. Revisit pregnancy risk assessments and consider additional rest breaks (particularly where sleeping and rest is difficult), modifying working hours or temporarily adjusting workloads.
In all cases, document your decisions and communicate clearly with employees.
Working parents and school closures
Schools in some areas are closing early or sending children home due to the heat. For working parents, this creates additional and unexpected childcare pressures.
Handle these requests with the same consistency and fairness you’d apply to any temporary hours adjustment or emergency leave situation.
Employees have the right to take unpaid time off for dependants in an emergency, but the spirit of good people management here is obvious: where you can flex, flex.
A parent managing a sudden school closure will feel additional pressure and stress so treat them accordingly – and remember, it is just a day or two.
Some of your employees may be at greater risk from the impact of the heat because of pre-existing medical conditions
Dress codes: comfort within reason
Now’s possibly not the time to enforce a strict dress code, unless there are strict health and safety requirements (best here to revisit your risk assessments and adjust accordingly).
Relaxing it is one of the simplest and most visible things HR can do to signal that it’s taking the heat seriously. Set clear parameters: comfortable and appropriate for a professional environment, not beachwear. Communicate the change clearly and specify when normal expectations will resume.
Where workwear is safety-critical – on construction sites, in certain clinical settings – the risk assessment conversation is more complex, but the principle is the same: protect people first.
Don’t get burned
Yes, working in the heat can be difficult; however, HR’s response to it should follow familiar principles: communicate clearly and early, apply policies consistently, make reasonable adjustments and put people’s safety first.
Having a clear plan which incorporates health and safety, employee support as well as setting expectations is key.
Temperatures rise and they fall – let’s use this as an opportunity to check-in with our staff and find the positives.
Can we use this as an engagement tool – after all, who doesn’t love an ice lolly?
Actionable insights
- Review risk assessments now: Prioritise outdoor workers, physical roles and anyone whose health condition could be aggravated by heat.
- Brief line managers before employees start asking: Give them a clear, consistent position on flexible hours, dress codes and breaks.
- Reach out to vulnerable employees proactively: Pregnant staff and those with chronic conditions may not raise it themselves.
- Get ahead of school closure requests: Decide your position in advance so the response is fair, fast and consistent.
- Document everything: Adjustments offered, communications sent and decisions made.
Read another article by Emma O’Connor: HR’s game plan for the World Cup 2026
