China is experiencing a relentless heat wave with temperatures forecast to exceed 40 C in parts of the country as residents prepare for the summer season to reach its peak on Sunday.

This week, scorching weather is expected to hit various parts of China, according to a warning issued on China Central Television's National Emergency Broadcasting WeChat account on Monday. In parts of Hebei and Shaanxi provinces, temperatures could surge as high as 42 C, creating sweltering conditions that are challenging historical records for this time of year.

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Cities including Zhengzhou in Henan province and Xi'an in Shaanxi province are facing six days of scorching heat, with temperatures expected to exceed 40 C. Zhengzhou may even witness 42 C on Tuesday, a close second to the city's highest recorded temperature of 43 C back in July 1966.

The oppressive heat is not just limited to daytime hours, as night temperatures in many areas, including the basins of the Yellow and Huaihe rivers, are hovering around 30 C, an unusual occurrence for this time of year.

Meteorologist Zhu Dingzhen said that over the past few years, he has observed how the summer heat in northern cities such as Beijing has started to resemble that of regions further south.

"Sauna days have grown longer, and even shaded spots in parks in Beijing are now sprouting moss, an uncommon sight before.

"The other day, I observed that the capital's relative humidity has hit 90 percent, whereas it stands at a mere 45 percent in Nanjing, Jiangsu province," Zhu said.

According to yearly data, the atmospheric water content has been on the rise.

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Data from the Beijing Meteorological Service showed that the average relative humidity of the city from 2013 to 2022 has increased by 5 to 10 percent compared to the period spanning 2003 to 2012, with this change more prominent during the summer months.

"However, it's premature to categorize the shift as warming and humidifying as fluctuations are inherent in nature. Monitoring climate change needs a 30-year observation period. Only when a consistent pattern is observed over this time frame can we assert a climate shift," Zhu said.

He added that when discussing disaster prevention and mitigation, authorities should focus on reaping benefits while averting harm.

"China's water conservation infrastructure has improved, and early warning and monitoring capabilities have been bolstered, alongside efforts to prevent flood-related disasters. Harnessing aerial water resources should secure a prominent place on the agenda," he said.

Contact the writer at lihongyang@chinadaily.com.cn