Shanghai residents and visitors had a late holiday bonus Friday when the sweet-scented osmanthus finally flowered across the city.

The blooming was nearly a week later than normal, but the flowers in Xuhui District's Xujiahui Park and People's Square in the downtown are now in full blossom, according to experts.

The late blooming also means the osmanthus are in flower at the same time as the cottonrose hibiscus and chrysanthemum, presenting a unique flower banquet for local residents.

"The blooming of the flowers has been delayed for about four to seven days because of the unexpected warm weather," said Wu Zhixing, a local gardening expert.

"But the late-coming sweet-scented osmanthus are expected to stay in full bloom for 10 days and next week will be the best time to appreciate them," Wu said.

However, the weathermen said there are clouds on the horizon that could dampen the experience.

Shanghai Meteorological Bureau said Friday that thunderstorms are expected to hit the city late Saturday, cutting the maximum temperature to 24 or 25 degrees Celsius.

The rain is not expected to last long, but cloudy skies will linger into tomorrow.

Meanwhile, the Shanghai Railway Administration Friday forecast that today and tomorrow would be the busiest days for people returning home by train after the holidays.

Administration officials said travelers began to return and extra measures are in place in the two stations in Shanghai to deal with the crowds.

They said 200,000 people arrived by train Friday and 185,000 departed.

Short-distance journeys among cities in the Yangtze Delta including Shanghai, Hangzhou, Nanjing, Wuxi and Suzhou were particularly busy during the holidays with people going home or travelling.

The administration has provided extra trains, but return tickets to popular scenic spots have been scarce, and visitors without return tickets will struggle to find seats back to places such as Beijing, Zhengzhou, Nanjing and Xi'an in the next few days.