BRITAIN is set to sizzle in 34C tomorrow with the MET Office issuing a level 2 heat warning. Temperatures will be higher than the Sahara.
But what does this mean if you're heading into work? We explain when it's legally too hot to do your job.
When are you able to go home from work if your office is too hot?
There isn't currently a legally defined maximum or minimum temperature for offices and other workplaces.
Employers are obliged to ensure the conditions are "reasonable" - but that depends on the kind of work.
Guidelines suggest a general minimum of 16C, or 13C for those doing physical work such as in factories.
The Health and Safety Executive (HSE) adds: "A meaningful maximum figure cannot be given due to the high temperatures found in, for example, glass works or foundries."
Those who work in food cold stores or bakeries can expect extremes of temperatures as part of the job.
But generally employers have a duty to "keep the temperature at a comfortable level" and provide clean and fresh air.
What rights do you have if it's too hot in the office?
Bosses should ensure their workers have access to water and monitor their wellbeing in hot weather, according to .
If you're a vulnerable employee – for example pregnant or menopausal, or you need to wear protective equipment so can't take off layers – that has to be taken into account.
The HSE says: “If a significant number of employees are complaining about thermal discomfort, your employer should carry out a risk assessment, and act on the results of that assessment.”
So if you're uncomfortable, tell your boss and if enough people complain they have to act, although that doesn't necessarily mean you can go home.
The Trades Union Congress (TUC) wants to make it illegal to keep people at work indoors if the temperature is above 30C.
It also wants bosses to supply cold drinks and fans and to relax dress codes in hot weather.
It has said: "When the workplace gets too hot it is more than just an issue about comfort - it can become a health and safety issue.
"If people get too hot, they risk dizziness, fainting, or even heat cramps."
What are the temperature recommendations for the workplace?
The UK will bask in 34C tomorrow before temperatures tumble over the weekend.
The Chartered Institute of Building Services Engineers recommends the following temperatures for different working areas:
• Heavy work in factories: 13°C
• Light work in factories: 16°C
• Hospital wards and shops: 18°C
• Offices and dining rooms: 20°C
I take public transport to work. What are my rights?
There isn't one rule for all public transport - companies have their own rules on what to do during the heat and so if there is an issue then you need to directly take it up with them.
In 2018, Londoners complained of unbearable temperatures of up to 42C on the Tube - higher than the legal limit for transporting cattle.
Transport for London said: “We understand travelling can be uncomfortable.
"There are air conditioned trains serving 40 per cent of the network.
"Customers should ensure they have water with them and contact a staff member if they feel ill.”
Transport for London has also assured sweltering commuters that all Tubes will be air-conditioned by 2030.
It's always recommended to bring a bottle of water with you if travelling in the heat, and if possible to wear cool, loose clothing.