On Friday, Astwood Bank in the West Midlands recorded the highest temperature of 34.7C.
Amber heat health alerts for southern England, the Midlands, and East Anglia will remain in place until Monday, the UK Health Security Agency said.
Less severe yellow warnings remain in place for northern England, while Scotland and Northern Ireland face warnings of wildfires on Saturday and Sunday.
Yellow weather alerts are issued during periods that are only likely to affect those who are particularly vulnerable, such as the elderly, and those with existing health conditions.
Amber alerts are issued in situations that could put the whole population at risk.
For the thousands expected to attend the Wimbledon finals this weekend, temperatures in south-west London will remain high on Saturday and are expected to reach 30C, possibly 32C in some areas, according the Met Office.
Sunday will see a slight dip to 29C in daytime highs, but the heat will remain with a chance of some places around London seeing 30C or above.