Extreme weather will continue to challenge airline punctuality through August, after bad weather caused massive flight delays and cancellations in June, the civil aviation authority said on Tuesday.

"In June, most regions experienced extreme weather conditions such as storms and heavy rain," said Zhang Chunzhi of the Civil Aviation Administration of China.

"Five major airports, in Beijing, Shanghai, Guangzhou and Shenzhen, which handle 40 percent of flights nationwide, had a combined 59 days of stormy weather and issued 92 massive flight delay and cancellation alerts."

Weather was still the chief obstacle for flight punctuality in June, accounting for 65.81 percent of delays, she said.

"There was more rain this June than in previous years. Extreme weather in some areas affected busy airports and flight routes. Take Beijing as an example, Beijing Capital International Airport had eight days of stormy weather in June, which caused 2,300 flight cancellations and more than 3,000 flight delays leaving Beijing."

She added that stormy weather also affected air routes in the Yangtze River Delta region and Pearl River Delta region, causing massive delays and some cancellations in Shanghai, Guangzhou and Shenzhen.

Flight punctuality will face further challenges from bad weather in July and August, Zhang said.

The China Meteorological Administration predicted temperatures will remain high in July and August, she said. "Northern China will have heat waves and periodic storms. Storms and typhoons will hit coastal areas in southern and eastern China," she said.

The administration re--quires airlines, airports, the air traffic management bureau and regional civil aviation departments to take responsibility to improve the punctuality rate during the summer storm season.

Storms often cause massive delays and cancellations, in which passengers get stuck at airports, causing chaotic scenes. Arriving flights cannot land, so they circle Beijing Capital International Airport, and some even return or land at other airports. After storms, airlines must apply to have flights rescheduled. Delayed and newly arranged flights then cause new delays.

The CAAC's North China Regional Administration launched initiatives to cope with such weather challenges, reducing air traffic operational risks and improving efficiency.