Last Sunday, December 1, was the first day of winter,the Shanghai Meteorological Bureau announced yesterday.

Winter becomes official when the average temperature is below 10 degrees Celsius for five consecutive days after the solar term lidong, or the start of winter, according to the traditional Chinese calendar.

The season arrived earlier this year, the usualdate is December 3 though last year it came on December 7.

Shanghai’s autumn was much shorter this year, however, lasting just 48 days, after it arrived later than usual on October 14. Autumn in the city is usually 62 days long.

Shanghai’s autumns and winters are getting shorter, the bureau said.

Summers have been some 28 days longer this century compared with the one before while autumns have lost two days and winter some 23 days. The number of spring days has remained the same.

Temperatures rose yesterday with an early morning reading at the Xujiahui meteorological station around 7 degrees, later rising to 12.8 degrees.

A weak cold front is expected to affect the city along with drizzle from last night, bringing temperatures down to between 6 and 10 degrees today when the skies will be cloudy to overcast.

Early mornings at the weekend will be colder, dropping to 5 degrees downtown, but later reach 12 degrees.