Is it too hot to work? UK temperature rules explained

Hot, dizzy or struggling to finish your shift? Tell the person in charge now and ask them to reduce the heat risk. There is no fixed legal maximum, but your employer must assess and control the danger. A thermometer reading alone does not decide whether you can leave.

What the law says

Regulation 7 of the Workplace (Health, Safety and Welfare) Regulations 1992 says the temperature in workplaces inside buildings must be “reasonable” during working hours. That is an enforceable standard, though it sets no number. The Regulations apply in England, Wales and Scotland. Northern Ireland’s 1993 Regulations use the same wording.

Regulation 7 also requires enough thermometers for people at work to check the indoor temperature and bars heating or cooling that releases harmful or offensive fumes. Regulation 6 requires sufficient fresh or purified air in enclosed workplaces; regulation 22 requires an adequate supply of wholesome drinking water. These are duties, not optional heatwave perks.

The Health and Safety at Work etc. Act 1974 requires employers to protect employees so far as reasonably practicable. Under regulation 3 of the Management Regulations 1999, they must assess risks from heat indoors and outdoors, then put controls in place and consult workers or their representatives. Northern Ireland has separate management regulations and its own regulator, HSENI.

What the 16°C and 13°C figures mean

L24 says indoor workplace temperatures should normally be at least 16°C, or 13°C where the work involves rigorous physical effort. They are cold-weather benchmarks, not a licence to ignore draughts, humidity or inadequate clothing. Take readings near the workstation, at working height and away from windows.

There is an exception where those figures would be impracticable, such as a loading bay that must stay open or a room where food must remain cold. The temperature should then be as close to the guidance figure as practical, with other measures to protect people. Workrooms are occupied for more than short periods, but other indoor areas still need a reasonable temperature.

Why there is no maximum and what replaces it

HSE explains why it sets no maximum. In bakeries and foundries, heat may come from the work, not the weather. A single ceiling would miss the difference between manageable heat and dangerous exposure. It would not relieve an employer of the duty to control risk.

Air temperature cannot tell you how safe the work is. HSE’s guidance requires employers to assess heat risks, act on them and review controls when the work or conditions change. Your employer does not get to wait until someone faints or the room reaches a union’s proposed threshold.

Our view: leaving workers without a maximum temperature hands employers the advantage. They choose which controls to fund; workers must make the case that conditions are dangerous, often while still on shift.

To assess heat, consider six things together: air temperature, radiant heat (sunlight or machinery), air movement, humidity, clothing or PPE, and physical effort. HSENI says an employer should act if fewer than 80% of people are satisfied with the thermal environment. That is a comfort guide, not a legal permission to expose the remaining 20% to danger.

Heat stress is more than discomfort

HSE lists heat rash, cramps, dehydration and heat exhaustion among the consequences of excessive heat. Heat stroke is an emergency and can be fatal. Someone who is confused, collapses or stops responding needs urgent medical help, not simply a glass of water and a return to the shift.

Start at the heat source. Shade glazing, insulate hot pipes or improve ventilation and cooling. Move heavy work to cooler hours, rotate tasks and provide a cool place to rest. Make water easy to reach and give people time to drink it. Loosen dress rules where safe, but do not remove essential protective kit on the job. PPE can make heat stress worse; PPE duties extended to limb (b) workers in April 2022.

Plan for more than a single hot week. UKHSA estimated 1,504 heat-associated deaths in England during five heat episodes in summer 2025; its interim May-June 2026 estimate was 2,877. These are population estimates, not deaths at work. Employers need a heat plan before the hot weather arrives.

What your employer must do

1. Assess the work. Cover indoors and outdoors, all six heat factors, PPE and people whose health makes them more vulnerable. The intensity and duration of a kitchen shift differ from desk work.
2. Consult and control. Discuss the assessment with staff or safety representatives; reduce exposure with shade, insulation, ventilation, cooling or changes to tasks and hours. Review controls when weather, plant or work changes.
3. Provide the statutory basics. Supply enough indoor thermometers, sufficient fresh or purified air in enclosed workplaces and adequate wholesome drinking water. A risk assessment does not replace these duties.
4. Protect individuals. Employers must consider pregnancy and health conditions in their assessments. After written notification of pregnancy, assess individual risks; where a risk cannot be avoided, change an employee’s conditions or hours, offer suitable alternative work, or suspend her on full pay. Consider reasonable adjustments when heat puts a disabled person at a substantial disadvantage.

Can you refuse to work in the heat?

There is no automatic walk-out temperature. In Great Britain, section 44(1A) of the Employment Rights Act 1996 protects a worker against detriment for leaving or refusing to return to a workplace where they reasonably believe danger is serious and imminent and they could not reasonably be expected to avert it. It also covers appropriate protective steps. The protection has applied to workers, including employees, since 31 May 2021. Section 100 separately makes dismissal of an employee for the equivalent reason automatically unfair, without a minimum service period.

1. Before you clock off, make a note. Record the time, place, heat reading if available, symptoms, work being done and what controls failed. Save messages and rota changes.
2. Put the risk in writing. Message your manager and safety representative: say what is happening, ask what will change, and keep a copy. If you are in immediate danger, get to safety first.
3. Get backup quickly. Contact your union or Acas. A grievance or appeal does not stop a tribunal deadline. Ask Acas promptly about early conciliation and the deadline that applies to your situation.

Agency workers should raise the risk with both the agency and the site operator. The party controlling the workplace must address hazards within its control. A genuinely self-employed contractor must assess their own work and does not acquire employment-tribunal walk-out rights merely by working on a client site; the site operator still has duties towards people working there. Acas says employers’ temperature duties also extend to home working. Northern Ireland has separate employment-rights legislation; article 68 provides corresponding detriment protection.

Will you be sent home and paid?

No law orders an office to close at 30°C or requires every employer to buy air conditioning. It requires effective controls. Fans may help in one room and simply blow hot air around another; if they do not reduce the risk, try something else. Employers can change hours, offer cooler work or send staff home.

Pay depends on contract and circumstances, not the temperature. If you are available for your contracted shift and the employer sends you home because the site cannot operate, your normal pay is generally due unless a valid lay-off or short-time arrangement applies. In a lawful lay-off, eligible employees may instead receive limited statutory guarantee pay; variable-hours arrangements need particular care. Staying away when the workplace is open and safe does not automatically entitle you to wages. If heat makes you ill and unable to work, check sick pay. See also lay-off rights and rest breaks; extra cooling breaks may be needed for safety even when statutory rest-break minimums have been met.

Outdoors, construction and schools

There is no fixed outdoor temperature rule, but your employer must assess heat risks. Direct sun, heavy lifting and insulating PPE can make outdoor work hazardous. Under construction-site rules, indoor working areas must have reasonable temperatures, outdoor sites need protection from adverse weather and rest facilities must be kept at an appropriate temperature. See our outdoor-work guide.

Classrooms have no legal maximum. In England, old school-premises temperature figures were replaced in 2012; do not mistake them for current law. Employers at schools still have to assess heat, ensure a reasonable indoor temperature and take action where needed. Which organisation is the employer depends on the school.

Who to report to, and what happens

Start with the manager, a safety representative or your union. In retail, ask USDAW; in health or care, UNISON; in hospitality, warehousing or delivery, Unite or GMB may be relevant. Record the time, location, conditions and readings, as HSENI suggests. Describe symptoms and failed controls alongside the number. In Great Britain, HSE regulates many industrial and public-sector workplaces, while local authorities usually cover offices, shops and hospitality. Report unsafe conditions to HSE; in Northern Ireland, contact HSENI or the district council. For serious danger, do not wait days to collect readings before seeking help or removing yourself from the risk.

If the problem includes underpayment, report wage theft through the HMRC minimum wage complaint route. Farmworkers recruited through the Seasonal Worker Scheme can raise exploitation with the GLAA. If heat-related treatment involves discrimination, contact the Equality and Human Rights Commission. For advice, contact Acas for early conciliation, Citizens Advice or a law centre. A union can help you raise the safety issue and protect your position.

Inspectors may issue improvement or prohibition notices and prosecute breaches. HSE may charge for time spent identifying and dealing with a material breach under Fee for Intervention; it is not a fixed heatwave fine. See HSE enforcement and employer safety duties.

Is a maximum temperature law coming?

There is no new limit in force. In June 2026 HSE said it was reviewing the Workplace Regulations’ guidance and Approved Code of Practice. A review is not a rule change. No new ceiling follows unless guidance or law actually changes. A Private Member’s Maximum Workplace Temperature Bill was introduced in 2026 to seek an independent recommendation, not to impose a 30°C threshold.