Visitors crowd an artificial wave swimming pool at a tourist resort to escape the summer heat in Daying county of Suining, Sichuan province, July 11, 2015. [Photo: Asiannewsphoto]

The National Meteorological Center (NMC) has issued a yellow alert for high temperatures as China is entering the height of summer.

A heat wave will hit central, eastern and northern China today with temperatures in some regions rising to around 40 degrees Celsius.

Since mid-May, some northern regions have been suffering from drought due to continued hot weather. Miyun Reservoir, one of Beijing's major water sources, has shrunk about 39 percent over the past year.

Wang Hua, premier weather broadcaster from the Beijing Meteorological Bureau says the capital will see a change in the weather later this week.

"Starting from next Wednesday, due to the impact of the upper vortex, Beijing will enter a stage with multiple thunderstorms. The temperature will also drop accordingly, with a high of around 30 degrees Celsius in the day and a low of 22 at night."

China has a four-tier color-coded weather warning system, with red representing the most severe weather, followed by orange, yellow and blue.