Sam Harrison
BBC News

Image source, Getty Images

It’s a huge weekend coming up for football fans, who are being urged to stay safe in the warm temperatures.

It's the last day of the Premier League on Sunday with games planned across England, and Wembley will be hosting the EFL final play-offs with around 170,000 fans expected across three days.

Supporters of the clubs involved - Hull City, Middlesbrough, Stockport County, Bolton Wanderers, Notts County and Salford City - have been told by Wembley to take extra care.

They've been advised to plan ahead, dress accordingly, and stay hydrated throughout the day, according to a statement seen by the BBC.

Let in cool air: Open windows on opposite sides of the home to encourage air flow. Do this when the air temperature outside is cooler than inside, which tends to be overnight or in the early part of the day.

Keep warm air out: During the peak heat of the day, keep your windows shut and blinds or curtains closed - especially on the side of your home where the sun is shining.

Use a fan: Putting the fan in front of an open window can encourage the fresh air from outside to be blown throughout the room - as long as it is cooler outside.

Limit hot activities: Ovens and cookers emit a lot of heat into the home during and after their use. Sticking to cold foods, such as salads, that don't require cooking can stop unnecessary heat being generated.

Cool yourself down: Tepid showers, wearing natural fibres like linen and cotton and using a cold water bottle on your body can help.

Find an alternative space: If your home is too warm, air-conditioned public buildings such as libraries, leisure centres and shopping centres can provide relief.

Image source, Getty Images

Network Rail, which manages many of the railways in Britain, has published some advice for those travelling by train in areas seeing warm weather.

They ask that, in hot weather, travellers:

• Check before travelling and allow more time for journeys
• Carry water bottles, which can be filled up at fountains at big stations
• Avoid boarding trains if feeling unwell, and ask staff for assistance at a help point if needed

Also with a warning is Southern Railway, which says trains are likely to be busier than usual, "particularly on routes to coastal destinations".

As a potential heatwave approaches parts of England, here's a look at how the weather across the UK will be over the bank holiday weekend.

Yellow vs amber

A yellow health alert means that adverse weather is likely to affect vulnerable groups.

An amber alert is issued when weather conditions could affect the whole population or the NHS, with travel disruption likely.

What are the risks?

TheUK's Health Security Agency (UKHSA) is warning that "significant impacts" are likely across health and social care services.

For places subject to yellow warnings:

These include a rise in deaths - particularly among those aged 65 and over or with health conditions - increased demand on health and social care services, and heat affecting the ability of the workforce to deliver services.

For places subject to amber warnings:

The same risks as above stand for places under amber alerts, but the UKHSA gives additional warnings that there could be issues managing medicines, an increased demand for power that exceeds capacity and that other sectors might start to notice issues, such as travel delays.

The amber alerts currently in place have been given a risk of 12, which means there is a 60-89% likelihood of these impacts.

It's worth noting that these heat warnings only cover England, and are not issued for other parts of the UK. Our earlier post covers which places are currently under warnings.

A few moments ago, the UK's Health Security Agency upgraded their heat health alerts in England, and issued new ones to previously unaffected regions.

Regions that have been upgraded from yellow to amber warnings are:

• East Midlands
• West Midlands
• East England
• London
• South East England

Regions upgraded from no alerts to yellow warnings are:

• North East England
• North West England
• Yorkshire and Humber
• South West England

All warnings are in place until Wednesday 27 May at 17:00 BST.

In our next post, we'll bring you more on what these alerts mean.

Simon King
Lead weather presenter, BBC Weather

The UK Health Security Agency (UKHSA) has just upgraded the heat health alert to amber for the Midlands, eastern and south-east England.

Yellow alerts have also come into force for south-west England and across northern England.

The alerts are in place from now until 17:00 BST on Wednesday.

We'll bring you a more detailed look on what areas are affected shortly.

It's just gone 10:00 BST, and the UK is bracing itself for a spurt of warmer temperatures. Here's how things stand right now:

London: 23°C

Manchester: 20°C

Cardiff: 18°C

Edinburgh: 18°C

Belfast: 16°C

Image source, BBC Weather

Michelle Roberts
Health editor

As we reported earlier, yellow heat health alerts have been issued for some parts of England this bank holiday weekend.

Heat health alerts give an early warning when temperatures are likely to impact on the health and wellbeing of the population. The core alerting seasons runs from 1 June to 30 September each year.

If the temperature goes high outside of this, an "extraordinary alert" is issued. If readings reach 30C before Monday, it will be the earliest date this has happened in the UK for over 70 years.

It doesn't necessarily mean temperatures will majorly affect people or that people should be very worried. A yellow alert is - for most people - unlikely to be a major problem.

But it's tells services, like GPs and ambulance crews, to prepare for a possible increase in dehydration, heat exhaustion and even heatstroke – which can be more serious.

Vulnerable groups like the elderly and very young are at higher risk. People are also being reminded to stay safe in the sun, by covering up, using sunscreen, seeking some shade and drinking enough water.

As heat health alerts are in place in parts of the UK, we've gathered some tips and tricks for keeping cool in higher temperatures.

Let's take a look across the UK this morning.

Both England and Wales are facing the warmer temperatures today, and the sunrise certainly showed up to prove it, with blue skies already showing.

Scotland and Northern Ireland have seen some cloud cover, but an otherwise pleasant morning. They're expected to face rain later today.

Image source, Fay C walking/BBC Weather Watchers

Image source, David e/BBC Weather Watchers

Image source, Fubsy/BBC Weather Watchers

Image source, Alioops/BBC Weather Watchers

It's 09:00 BST, which means that various heat health alerts have now come into force across parts of England.

Yellow alerts have been issued for five regions: the East Midlands, the east and south-east of England, London and the West Midlands.

They will remain in place until 27 May at 17:00.

• You can read more details on the alerts here

Throughout the long weekend, the ultraviolet (UV) levels will be very high for many places. High UV corresponds to an index of 6 or 7 on a scale from 0 to 11+.

During summer in the UK, that UV index would typically be around 5-6 with a maximum of 8 only in exceptional circumstances.

Is UV dangerous?

Warm weather can often bring high levels of UV radiation, which is emitted by the Sun and penetrates the Earth's atmosphere.

UV is not always dangerous. It can be beneficial because it enables our skin to produce essential vitamin D.

This is important for the function of bones, blood cells and our immune system.

But every exposure can also increase the risk of skin cancer, which UV radiation can cause by damaging DNA in skin cells.

It also plays a substantial role in skin ageing, contributing to wrinkles and loosened folds.

What is the UV index?

Levels of UV radiation vary throughout the day. The highest readings occur in the four-hour period around "solar noon", when the sun is at its highest - usually from late morning to early afternoon.

The higher the number, the greater the potential for damage to the skin and eyes - and the less time it takes for harm to occur.

Simon King
Lead weather presenter, BBC Weather

For many of us today will be the first of some very warm or hot days ahead.

With lots of sunshine across England and Wales, temperatures will widely get into the low to mid 20s.

The warmest weather will be around East Anglia and south-east England where temperatures of 27 or 28 degrees are expected. There’s even a small chance it could be as high as 29 or 30C in the Cambridgeshire area.

With cloudier skies in the far west of England and Wales, Northern Ireland and Scotland, it’ll be cooler with highs of 15 to 18C. But even cooler in the Northern and Western Isles at 13C.

Is the mercury ticking up in your area, or are grey skies lingering? Send us your updates and pictures.

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Image source, Rossi/BBC Weather Watchers

While things may be bonnie in England and Wales, it's not the same picture for the rest of the UK.

Many in Scotland and across the hills in Northern Ireland will face a cloudy start to the day, with rain expected in the afternoon.

Scotland's central belt will reach 20C later on, and the north east will see 22C, but the higher you go, the lower the temperature. Residents of Shetland can expect highs of 13C.

But there will be some sunny spells scattered across both Scotland and Northern Ireland.

Many parts of England will likely enter an official heatwave in the coming days, but Scotland and Northern Ireland are unlikely to meet the threshold.

So, what does it take for an official heatwave to be declared?

The timeframe: For a heatwave to occur, a location needs to record a period of at least three consecutive days with daily maximum temperatures meeting or exceeding the temperature threshold.

Differing thresholds: The threshold varies by area across the UK - in Scotland and Northern Ireland for example its 25C while in London it's 28C.

Temperatures in coming days: Over the bank holiday weekend, the south-east of England is predicted to reach 33C, but Scotland only 22C.

How do heatwaves happen? Our BBC Weather team explain in the video below:

Various heat health alerts are taking effect across parts of the UK from 09:00 BST today.

Heat health alerts, not to be confused with the Met Office's weather warnings, are issued by the government's UK Health Security Agency (UKHSA).

Currently, there is a yellow heat health alert in place until 27 May at 17:00 BST in the following places:

• East Midlands
• West Midlands
• East of England
• London
• South-east of England

Yellow alerts focus on people who are particularly vulnerable - such as older adults and those with certain long-term health conditions.

The graphic below takes a closer look at what the different health alert levels mean:

Image source, EPA-EFE/Shutterstock

Temperatures in parts of the UK are forecast to rise to as high as 33C as a potential heatwave develops across the long bank holiday weekend.

The UK Health Security Agency has issued yellow heat health alerts - which suggest risk to vulnerable people - across much of the Midlands and south-east England.

They will be in place from 09:00 BST on Friday until 17:00 on Wednesday.

Heat health alerts are usually only issued between 1 June and 1 September but authorities have chosen to issue an "extraordinary" alert for this period of warm weather.

Bank holiday Monday could see the hottest May day on record, as there is increasing confidence that the maximum temperature could reach 33C. This would exceed the current highest recorded May temperature of 32.8C, set in 1944.

Parts of England could also enter an official heatwave this weekend, and parts of Wales could after the bank holiday.

As the sunshine becomes more widespread across the UK, UV levels will also rise to "high" for many.

While it won't be as hot in Scotland and Northern Ireland with no heatwave expected, it will still feel warm over the coming days.

We'll bring you the latest forecasts, developments and top tips to stay cool during the warm weather on this page - stay with us.