Home » Extreme Hot Weather in the Workplace
Quick answer: There’s no legal maximum workplace temperature in the UK, but employers have a legal duty to assess and manage heat as a workplace hazard. Official guidance from the HSE, ACAS, UKHSA and EU-OSHA all point to the same practical step: relax dress codes and move to lighter, breathable, looser-fitting clothing during extreme heat. For organisations with a branded, customer-facing uniform, “relax the dress code” isn’t a real option, which means the uniform itself has to be engineered to perform in the heat, not just look good in a photograph.
As of today, six regions of England, the West Midlands, East Midlands, South East, South West, London and the East of England, are under a red heat-health alert from the UK Health Security Agency (UKHSA), running until 11pm on Thursday. A red extreme heat warning has also been issued by the Met Office. This is the second time in as many summers that UK employers have been told, in explicit terms, that the heat their staff are working in is a health and safety issue, not just a comfort one.
For any organisation with thousands of uniformed staff on shop floors, forecourts, depots and front-of-house, the question isn’t whether extreme heat will happen again. It’s whether the uniform programme can cope with it when it does.
The UK has no statutory maximum workplace temperature. The Health and Safety Executive (HSE) has been clear that “every workplace is different” and that an upper legal limit isn’t workable across such varied environments. But that doesn’t mean employers are off the hook.
Under the Workplace (Health, Safety and Welfare) Regulations 1992, employers must provide a “reasonable” temperature in indoor workplaces. Under the Management of Health and Safety at Work Regulations 1999 every employer has a legal obligation to assess risks to staff health and safety and the HSE has confirmed this explicitly includes risks from extreme weather events such as heatwaves. Heat is classed as a hazard, in the same category as any other workplace risk.
In a press statement issued this week HSE Deputy Director John Rowe put it plainly: “Last summer should have been a wake-up call for all employers. If we continue to experience hotter summers, this could have a big impact on the workforce of this country, affecting everything from health of workers to productivity.”
Pulling together the current advice from HSE, ACAS and UKHSA, the recommended practical measures are consistent:
That last point, relaxing the dress code appears in almost every piece of official guidance currently in circulation. ACAS goes further, noting that while employers aren’t legally obliged to relax uniform requirements, “where possible it may be advisable” to do so, particularly around ties, jackets and other formal layers.
It’s sound advice for an office. It’s far harder to apply to a retail, hospitality, transport or manufacturing workforce wearing a branded uniform that exists, in part, to make staff instantly identifiable to customers.
“Relax the dress code” assumes there’s a dress code to relax, a tie that can come off, a jacket that can stay in the locker. For a uniformed workforce, that flexibility doesn’t really exist. Strip away the branded layer and you lose the thing the uniform was bought to do: make your people recognisable as your business, not someone else’s.
This is precisely the gap between official heat guidance and the operational reality for large UK employers. The advice is correct as far as it goes, but it’s written for a generic workplace, not for an organisation whose people front the brand all day, every day, in whatever the weather decides to do.
The result is that “relaxing the dress code” during a heatwave usually means staff making their own ad hoc adjustments eg rolled sleeves, untucked shirts, swapped-out layers that undo months of work on brand consistency, at exactly the moment customers are most likely to notice.
If you can’t relax the uniform, the next official lever is the uniform’s construction. Guidance from the European Agency for Safety and Health at Work (EU-OSHA) and the UKHSA’s joint advisory with HSE on heat stress, converge on the same physical principles:
UKHSA’s guidance is explicit that any garment which “reduces the body’s ability to evaporate sweat and prevents heat loss through convection and radiation” raises the risk of heat exhaustion and heat stroke. That’s a description that applies to a surprising number of standard off-the-shelf workwear ranges, which are typically specified for durability and cost rather than thermal performance.
This is where uniform design stops being a branding exercise and becomes a health and safety one. A uniform that hasn’t been engineered with fabric weight, weave and colour in mind isn’t just uncomfortable in a heatwave. By the government’s own definition, it’s a contributing factor to a recognised occupational health hazard.
The organisations that handle extreme heat well aren’t the ones scrambling to relax a dress code mid-alert. They’re the ones whose uniform was engineered for the wearer’s actual working conditions from the outset. In the same way a uniform engineered for a driver needs discreet pleats for comfort behind the wheel, or a uniform engineered for an automotive technician needs covered zippers and reinforced elbows. Climate is simply another functional requirement, alongside fit, durability and brand. It belongs in the design brief, not in a hastily issued summer memo.
That means treating fabric specification (weight, weave, breathability, colour) as seriously as logo placement when a uniform programme is designed or reviewed, and building wearer trials into hot working environments before garments are signed off, not after the first heatwave complaint lands in HR.
Four questions worth asking before the next heat-health alert lands:
1. Do you know which of your current garments are heavyweight, dark-coloured or low-breathability fabrics, and where your highest-heat-exposure roles and sites are?
2. If you “relaxed the dress code” tomorrow, what would staff actually be permitted to wear and would they still look like your brand?
3. Do your line managers know the official guidance on heat stress symptoms, breaks and hydration well enough to act on it without waiting for HR?
4. Has your uniform programme ever been wearer-trialled in genuinely hot conditions, or only assessed for durability and cost?
If the honest answer to any of these is “no” or “not sure,” that’s a reason to get in touch with our Uniform Specialists and begin the conversation about how you can optimise your company uniform and future proof your success.
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No. The UK has no statutory upper temperature limit for workplaces. Employers must instead assess heat as a workplace hazard under the Management of Health and Safety at Work Regulations 1999 and take reasonably practicable steps to manage the risk.
No. ACAS confirms employers are under no legal obligation to relax dress codes during hot weather, though it's recommended as good practice where it's practical to do so.
HSE and UKHSA guidance recommends weather-appropriate PPE and clothing, relaxed dress codes where possible, and breathable, loose-fitting, light-coloured garments that allow sweat to evaporate and reduce the risk of heat stress.
Heat stress occurs when the body can't cool itself enough to maintain a safe temperature. It can progress to heat exhaustion (headache, dizziness, excessive sweating, fast pulse) and, if untreated, heat stroke, which is a medical emergency. UKHSA guidance lists the symptoms and recommended actions.
Yes, but it has to be designed that way. Fabric weight, weave, colour and fit all affect thermal performance. A uniform engineered with breathability and climate in mind from the outset doesn't need to be abandoned the moment temperatures rise.
Best practice is to review fabric specification whenever a uniform programme is refreshed or redesigned, and to wearer-trial garments in the actual conditions staff will work in ( including peak summer heat0 rather than relying on supplier spec sheets alone.
