The Shanghai World Expo on Saturday recorded the largest daily number of visitors of more than half a million since its opening on May 1, said a report on the official website.
The number of visitors reached 290,000 by 10:30 a.m. and rose to 503,600 by 8:30 p.m., the report said.
Organizers attributed the sudden increase of visitors to the end of rainy days in Shanghai at the weekend.
In response to the sudden surge, Australia and Thailand pavilions postponed their closing hours to 11 p.m. and 22:30 p.m. respectively.
The Expo attracted some 200,000 visitors on its opening day. Organizers expect about 70 million people to visit the Shanghai World Expo during its six-month duration, or 380,000 per day.