New rounds of drenching rain will continue in the capital this week, after a Sunday downpour put an end to the oppressively hot and hazy weather.

"Torrential rain will cover the whole city and continue for the whole night, with rainfall reaching 40 to 70 millimeters, equivalent to that of June 23, which threw the whole city into chaos," Wei Jianming, the chief engineer of the Beijing Meteorological Bureau, told China Daily on Sunday.

Highs this week will reach 34 C, Wei said.

A man rides an electric bike in the rain on the north Fifth Ring Road on Sunday. Downpours hit the capital again, cooling down the suffocating temperature. [China Daily]

"But we cannot say for sure that the sauna-like weather, with high temperatures and high humidity, will continue, because humidity is difficult to predict," Wei said.

The highest humidity was recorded at 90 percent on Saturday night. The humidity lingered for just two days, but it had a big impact.

"High humidity would make people feel short of breath, especially senior citizens with coronary heart disease.

"Also, suspended particles like dust cannot disperse in such weather and will harm human respiratory systems," said Lu Haitao, an emergency room doctor at the China-Japan Friendship Hospital.

He said eight of the 21 patients he saw on Sunday had respiratory problems.

A female student surnamed Chen had to be treated for an inflammation of the tonsils. Her mother, who accompanied her, said: "Many of her classmates asked for sick leave at the weekend, for they also had colds and sore throats."

Zhu Guanghua, 70, was confined to bed and received a transfusion at the hospital for cerebral vascular insufficiency. His son said that Zhu had been sedentary for a long time, which "made my father sick, as the doctor told us.

"But it's uncomfortable to walk outside, too hot and too easy to get sunstroke," said the son. He told China Daily that it was the sauna-like weather that had forced his father to remain in a room with air conditioning.

The hot, humid weather also caused heavy fog, which cut visibility on some expressways to less than 500 meters on Sunday morning.

No flight delays were reported as of Sunday morning.

"Though I felt short of breath, the sauna-like weather brought me a good day. More people turned to travel by taxi," a taxi driver surnamed Wang told China Daily on Saturday afternoon.

"Many people gave up on the buses after waiting for more than 10 minutes. It's terrible to be crowded with sweaty people around."

The municipal meteorological department advised residents to avoid dehydration and getting wet.

The National Meteorological Center (NMC) issued a blue alert for heavy rain at 10 am on Sunday, the lowest level of China's four-color warning system for rainstorms, warning that torrential rain and thunderstorms would hit North China in the following 24 hours.

The observatory said thunderstorms would hit most of North and Northeast China from Sunday to Monday.Red is the most serious type of alert, followed by orange, yellow and blue.

The NMC also warned the public about the danger of lightning strikes.

The NMC maintained its blue alert for heat waves in China's southern regions, stating that high temperatures will persist in most southern provinces, as well as parts of the Xinjiang Uygur autonomous region and the western Inner Mongolia autonomous region.

Temperatures are expected to exceed 35 C from Sunday to Tuesday in these places, according to the center's predictions.