Temperatures in Salisbury and Greater London reached 18C by 5am, according to the Met Office.
Thousands of people watched the sunrise over Stonehenge to celebrate the summer solstice, signifying the end of spring.
Those who gathered for the spectacle on Saturday at the neolithic monument in Wiltshire braved a warm start to the morning as they marked the year’s longest day.
Temperatures in Salisbury and Greater London reached 18C by 5am, according to the Met Office.
The weather bureau confirmed that Yeovilton in Somerset and Crosby in Merseyside recorded the highest overnight temperatures in England, both reaching 19.7C by 6am on Saturday.
Towns in Cumbria and Lancashire also recorded temperatures above 19C.
An amber heat-health alert for all regions in England remains in place for the weekend.
Solstice events at Stonehenge mark some of the rare occasions visitors are allowed close to the stones at the World Heritage site.
In the lead up to the event, both Stonehenge and Wiltshire Police posted social media warnings about heavy traffic and pedestrians.
Stonehenge is a monument built on the alignment of the midsummer sunrise and the midwinter sunset.
On the summer solstice, the sun rises behind the Heel Stone -the ancient entrance to the Stone Circle – and rays of sunlight are channelled into the centre of the monument.
It is believed solstices have been celebrated at Stonehenge for thousands of years.
The summer solstice takes place as one of the Earth’s poles has its maximum tilt toward the sun as it reaches its highest position in the sky, ensuring the longest period of daylight for the year.
English Heritage curator of history Jennifer Wexler said people had been marking the solstice at the stones going back thousands of years.
“The solstice at Stonehenge is one of our most special moments,” she told an English Heritage live stream.
“It’s the longest day of the year, but also the time when the sun is the highest in the sky.
“We think people were marking it here on site and gathering here for thousands of years.”
The Met Office confirmed that “many places” in England and “one or two areas” in Wales, including Cardiff, entered a heatwave on Friday.
The amber heat-health alert, issued by the UK Health Security Agency (UKHSA) for the first time since September 2023, is in force until 9am on Monday.
