Some parts of West Yorkshire, Cornwall, Devon and Wales have hit heatwave criteria for the first time since June - following three consecutive days at or above their threshold temperature.

Heat health alerts have been upgraded to amber for most of England until 9pm on Sunday, as people have been making the most of the sunshine as temperatures rise.

The warning covers every region apart from the North East, where a yellow alert is in place.

The UK's highest temperature of the year so far of 32.2C (89.9F) was recorded on 10 and 25 June.

There is a chance that could be exceeded today or tomorrow, the Met Office said.

The forecaster said 32C (89.6F) is expected on Wednesday and 33C (91.4F) on Thursday, which is expected to be the peak.

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"It will then be 32C right the way until Sunday for some places in the south," said meteorologist Amy Bokota.

She revealed that 13 weather stations have officially marked a heatwave already - and this is set to rise in the next couple of days.

Sky News weather presenter Kirsty McCabe said the last time the highest temperature of the year occurred in September was in 2016, when Gravesend reached 34.4C (93.9F) on 13 September.

Tropical nights are possible, where temperatures may not drop below 20C (68F).

The highest overnight minimum temperature for September on record is 21.7C (71F) - and this record could be threatened tonight and tomorrow night in particular, the Met Office said.

The exception to the largely very warm conditions this week is the far north and west of Scotland, which will see some periods of showery rain at times.

There is also a chance of some isolated thundery showers crossing areas to the west from Tuesday, more significantly at the weekend.

Read more:
What is a 'heat dome'?
How do heat health alerts work?

Meanwhile, according to the World Meteorological Organisation (WMO), Earth has endured the hottest Northern Hemisphere summer on record.

Last month was not only the hottest August scientists have ever recorded, it was also the second-hottest month measured - behind only July 2023.

August was about 1.5C warmer than pre-industrial averages, which is the warming threshold that the world is trying not to pass. However, that 1.5C threshold is over decades - not just one month.

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The world's oceans - more than 70% of the Earth's surface - were the hottest ever recorded - nearly 21C (69.8F) - and have set high temperature marks for three consecutive months.

"The dog days of summer are not just barking, they are biting," UN Secretary-General Antonio Guterres said in a statement. "Climate breakdown has begun."