Summer in the UK has kicked off with a record-shattering heatwave that saw temperatures climb to extreme levels across the country.While weather warnings have been lifted and average temperatures have returned for most, forecasters expect the next heatwave could arrive within a matter of weeks.The hottest weather is typically felt in July and August, despite the UK already experiencing two heatwaves this year and breaking the record for the hottest spring ever in England and Wales. The Met Office has said a warming climate and expected El Niño weather event meant that the chance of a hot summer is higher than normal, which could increase the risk of heatwaves and other heat-related impacts. In its three-month summer outlook, the weather agency said temperatures during the period of 11 to 25 July are “likely to be above normal on the whole, with a greater than normal chance of hot conditions developing at times.” A forecast for July shows temperatures could hit 36C in London (WXCharts)It adds that there is potential for “changeable or more unsettled conditions developing later in the period, with a risk of some heavy and thundery showers.” The Met Office said that having a hot summer is twice as likely now than it was between 1991 to 2020.Forecasting platform WXCharts expects typical summer temperatures over the next week, before a possible third heatwave returns in southern England. From 7 July, temperatures could reach 32C in southeast England and reach a high of 36C in the capital on 8 July, and 35C the following the day. It estimates that temperatures will reach the high twenties in the days that follow.The Met Office has said that the likelihood of temperatures exceeding 40C in the UK is increasing. According to the World Meteorological Organisation, the chances of seeing unprecedented temperatures of 40C or more in the UK could be up to 10 times more likely in the current climate.Temperatures hit a June record of 37.3C on Friday (PA)During the June heatwave, rare red extreme heat weather warnings, which had only ever been issued in 2022, were in force across large parts of the country.The UK saw three consecutive days of record temperatures, peaking at 37.3C in Santon Downham, Suffolk, on Friday.Scientists have warned that intense heat events will become increasingly common and the UK could temperatures reach 45C in the near future.Professor Stephen Belcher, Met Office chief scientist, said: “Heatwaves in the UK are becoming more frequent and intense. “The duration of the extreme heat combined with high humidity will present severe challenges for communities and the health of individuals.” He added: “Weather is the national conversation in the UK and the summer of 1976 lives on in many memories. “Since then our climate has fundamentally changed, with average UK summers having warmed by around 1.4C. “Crucially extremes have changed too.”