Beijing's temperature soared past 40 degrees Celsius (104 degrees Fahrenheit) again Thursday, as the Chinese capital grapples with what is shaping up to be one the most severe heat waves on record.

Since 1951, Beijing has seen temperatures rising above 40C (104F) on 11 days -- and five of them occurred over the past two weeks.

The city of 22 million has already seen a new record for its hottest day in June, with a high of 41.1C (106F) registered on June 22.

China has been gripped by scorching heat waves for weeks, which authorities said had arrived earlier and been more widespread and extreme than in previous years.

Northern China, a heavily populated region with hundreds of millions of residents, has been particularly hard hit.

On Thursday, nine national-level weather stations in Beijing and the neighboring province of Hebei registered the hottest temperature for July ever recorded.

On Thursday morning, Beijing issued its second red alert for heat in two weeks -- the highest in a three-tier warning system.

The city government advised outdoor work to be suspended when temperatures run high, and ordered authorities to take emergency measures to prevent heatstroke.

Beijing's culture and tourism bureau has also urged tour groups to minimize outdoor excursions. Last Sunday, a 48-year-old tour guide died of heatstroke in the Summer Palace, a vast imperial garden in northwest Beijing, according to state media.

Since June, Beijing's medical emergency hotline has been receiving an average of 30 calls a day related to heatstroke, the state-run Beijing Daily reported.

The persistent heat waves have put huge stress on the country's power grids as demand for air-conditioning soared, with some local governments urging companies and residents to curb the usage of electricity.

Some train stations, including in Henan and Hunan provinces, have placed big blocks of ice inside the departure hall to bring down temperatures.

The extreme temperatures have boosted the demand for sunproof products, including the "facekini," a full-face mask to protect against the sun with holes for the eyes, nose, and mouth, according to state broadcaster CCTV.

As the climate crisis intensifies, scientists say dangerous, record heat waves are set to become more frequent and more severe.

Chinese scientists have warned against more extreme weather events this year, citing the onset of El Niño -- a natural climate pattern in the tropical Pacific Ocean that brings warmer-than-average sea-surface temperatures.

The phenomenon has a major influence on weather across the globe, affecting billions of people.

On Tuesday, the World Meteorological Organization warned that the onset of El Niño would greatly increase the likelihood of breaking temperature records and triggering more extreme heat in many parts of the world and in the ocean.

Tuesday saw the hottest global temperature ever recorded -- at 17.18C (62.9F), breaking the previous record of 16.92C set in 2016, during the previous El Niño event.