BEIJING, July 12 -- The National Meteorological Center (NMC) on Sunday 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 on Monday with temperatures in some regions rising to around 40 degrees Celsius, the NMC forecasted.

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.

"The upcoming heat wave will even worsen the drought. Local governments should work to reduce its impact on agricultural production," said the weather observatory.

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