Although the Great British Summer often doesn't result in hot temperatures there will be times when the sun does come out and workers find themselves working in hot conditions. In the UK there is no maximum temperature that a workplace is allowed to be, rather advice from the Health & Safety Executive (HSE) states "during working hours, the temperature in all workplaces inside buildings shall be reasonable". What is reasonable depends on the type of work being done (manual, office, etc) and the type of workplace (kitchen, air conditioned office, etc).
The HSE offers further guidance on workplace temperatures including details on carrying out an optional thermal comfort risk assessment if staff are unhappy with the temperature - Health and Safety Executive (HSE) - Temperature.
Generally hot weather shouldn't affect journeys to work, but occasionally in the UK there might be an impact on public transport if temperatures go over a certain level. Train companies may limit the speed of trains in case the tracks buckle which may result in the late arrival of your train. You should check with your local train company to see if speed restrictions are in place or cancellations are expected and plan accordingly.
While employers are not legally obliged to provide air conditioning in workplaces they are expected to provide reasonable temperatures. If you have air conditioning switch it on, if you have blinds or curtains use them to block out sunlight and if you're working outside wear appropriate clothing and use sun screen to protect from sunburn.
It is also important to drink plenty of water and employers must provide you with suitable drinking water in the workplace. It is important to drink water regularly throughout the day and not to wait until you are thirsty as this is an indication that you are already dehydrated.
Many Muslims will fast each day from sunrise to sunset during Ramadan (Islam) as part of their faith. This includes not eating food, drinking liquids or smoking. When Ramadan falls in the summer months it can be particularly challenging as the days are longer. Employees may wish to use annual leave when observing the Ramadan rules, and employers may help by holding meetings etc. in the mornings when energy levels are higher. Where possible employers could consider a temporary change in working hours.
The hot weather can make workers feel tired and less energetic especially for those who are young, older, pregnant or those on medication. Employers may wish to give these workers, more frequent rest breaks and ensure ventilation is adequate by providing fans, or portable air cooling units.
Employers often have a Dress code in the workplace for many reasons such as health and safety, or workers may be asked to wear a uniform to communicate a corporate image. A dress code can often be used to ensure workers are dressed appropriately.
While employers are under no obligation to relax their dress code or uniform requirements during hot weather, some may allow workers to wear more casual clothes, or allow "dress down" days. This does not necessarily mean that shorts and flip flops are appropriate, rather employers may relax the rules in regards to wearing ties or suits.