China's National Meteorological Center (NMC) upgraded its high temperature alert from "blue" to "orange" on Tuesday, the second most serious level in China's four-color heat warning system, as hot weather is expected to persist in northern China in the next 24 hours.

Maximum temperatures in north China, including Tianjin Municipality and some parts of Hebei Province, climbed above 38 degrees Celsius Tuesday, while the mercury hovered around 40.6 degrees Celsius in Beijing, a record high for the same period in the Chinese capital.

In the next 24 hours, areas in provinces of Hubei, Shanxi, Gansu and Inner Mongolia Autonomous Region are forecast to swelter under maximum temperatures ranging from 35 to 38 degrees Celsius.

But the NMC forecasts that rain would hit north China in the coming two days to cool the scorching weather. Experts said high temperatures are likely to end on Thursday with the arrival of the rains.

China has a four-color heat warning system: red, orange, yellow and blue. Red is the most serious level.