By Tuesday afternoon, at least 86 Chinese cities in the eastern and southern parts of the country had issued heat warnings. Chinese meteorologists predict that temperatures in some cities will exceed 40 degrees Celsius in the next 24 hours. In Shanghai, China’s most populous city, authorities told its 25 million residents to prepare for unusually hot weather. Since record keeping began in 1873, Shanghai has only had 15 days with temperatures above 40 degrees Celsius. “It’s too hot for July,” said Wang Ying, 35, who lives in Shanghai. “My air conditioning has been running all day today and I don’t dare go outside at all – even on my balcony.” He said he planned to work from home for the week. Heat-related mortality has increased fourfold from 1990 to 2019, reaching 26,800 deaths in 2019, according to a Lancet study published in 2020. People aged 65 and over face a 10.4% higher risk of dying during a heat wave. the study said. As a result, many Chinese cities are warning about the danger of such high temperatures for the elderly. In the eastern city of Nanjing, one of China’s three “ovens” notorious for their sweltering summers, city officials opened underground air raid shelters to locals from Sunday, with its wartime warehouses equipped with wifi, books , water dispensers and even. microwave ovens. In Chongqing, another furnace city, the roof of one of its museums melted, with the tiles of a traditional Chinese roof cracking as the heat dissolved the underlying tar. The city declared a red alert on Monday. High temperatures, humidity and ultraviolet radiation are also predicted to envelop the central city of Wuhan, the third furnace city. In the US, the southwest and central regions have experienced extreme heat, with 42.2 degrees Celsius in Waco among more than a dozen daily temperature records broken over the weekend in cities in Texas, Colorado, Oklahoma and Arkansas. A “heat dome”, an area of high pressure that traps heat, has been blamed for the spike in what was already a hot summer. Texans reeling under record temperatures and high humidity have been urged to conserve energy as the power grid struggles to cope with rising demand. The non-profit organization Eagles Flight Advocacy and Outreach delivers a fan to Juanita Alarcon at her apartment in San Antonio, Texas. Photo: Reuters Temperatures in Texas are forecast to drop by the end of the week while they rise in Arizona, reaching 45C in the state capital, Phoenix, on Friday. In Europe, Spain is in the grip of its second heat wave of the summer, with temperatures in some southern and southwestern regions reaching or exceeding 44 degrees this week. Ruben del Campo, a spokesman for the state meteorological agency, Aemet, said the heatwave, which began last Saturday, is expected to peak between Tuesday and Thursday but could extend into next weekend. “This will be an intense heat wave and temperatures on the hottest days could reach or even exceed 44 degrees Celsius in the Guadiana and Guadalquivir valleys and in cities such as Córdoba or Badajoz,” Del Campo said, adding that the Ebro valley and the southern parts of the north-west region of Galicia could see temperatures of 42 C. As well as the “very high risk of bushfires”, he said, the heatwave meant night-time temperatures in many places would be uncomfortably high. “There will be stormy, tropical nights in some central, western and southern parts of Spain when the temperature will not drop below 25C,” he said. “This means that at the time when most people usually go to bed – between 10pm and midnight – temperatures in some places can be between 32 and 34 degrees Celsius.” Del Campo said that while the heat wave was not on track to match the 26-day heat recorded in June and July 2015, nor the 16-day heat in late July and early August 2003, it could rival previous heat waves for the third position. Although the first official heat wave of the Spanish summer in mid-June brought temperatures as high as 42 degrees Celsius, some parts of Spain experienced a sharp rise in temperatures last month after the hottest May on record pushed the mercury past 40 degrees in certain areas. Spain recorded its highest ever temperature last August, 47.4 degrees Celsius in the Andalucian city of Montoro. A street thermometer reads 47C in Ourense, Spain, on Tuesday. Photo: Miguel Vidal/Reuters Across Portugal’s border, temperatures soared past 44C last weekend, sparking wildfires, with huge plumes of smoke visible in the capital, Lisbon. Firefighters brought the largest fire under control on Monday after it burned through parts of the central municipality of Urem, local officials said. While temperatures eased somewhat in Portugal on Monday, they were expected to soar again in the coming days, with 44C for the southeastern city of Evora. Subscribe to First Edition, our free daily newsletter – every morning at 7am. BST “In the coming days we will experience conditions of maximum risk,” Prime Minister Antonio Costa said. “The slightest lack of vigilance could lead to a fire of significant proportions.” A front of warm air began pushing into France on Monday, with temperatures topping 30 degrees Celsius across much of the country, according to the national meteorologist, Météo-France. It said temperatures on Tuesday could reach 39C in some parts of France, adding that the heat wave was expected to peak from Saturday to next Tuesday.