Early snow in Shanghai affected air traffic and may cause ice on the road.

The first snowfall this winter in Shanghai on Wednesday afternoon came about 20 days earlier than in past years, said Zhang Ruiyi, premier service officer with the Shanghai Meteorological Bureau.

The city's meteorological observatory issued a yellow warning signal on road icing on Wednesday afternoon, with icy roads possibly affecting traffic.

The snowfall was not heavy but dragged temperatures below 0 C, with predicted further drops to -2 C by Thursday morning, said Zhang.

As many as 12 flights were delayed due to snow at Hongqiao International Airport and Pudong International Airport between noon and 3 pm on Wednesday, and four other flights were canceled.

Highways were not closed but speed limits from 60 km/h to 80 km/h were posted.

The Shanghai Railway Bureau launched a contingency plan to ensure trains were not affected, according to Tao Liping, spokesman with the bureau.

The Shanghai Municipal Bureau of Civil Affairs set up shelters for the homeless and street beggars.

Those who are in need of a shelter may seek help at the shelters in each district.