Summer has arrived and it's the earliest on record, the Shanghai Meteorological Bureau said yesterday.

A little boy tries to cool himself down in the fountain at People's Square in Shanghai yesterday. [Zhang Suoqing/Shanghai Daily]

The city officially entered summer on Wednesday, as the daily temperature has been higher than 22 degrees Celsius for the past five days.

At present, the warm air mass above the city is strong and stable and a sandstorm in northern China has prevented a cold front from moving south, which has led to the extended period of unseasonably warm weather, weathermen said.

Sunny skies and a high of 34 degrees is forecast for today, but the temperature will drop to 31 degrees tomorrow with the chance of a thunderstorm. It will be even cooler on Wednesday with a high of 25 degrees, meteorologists said.

The forecast predicts sun and a high of 30 degrees on Thursday.

Yesterday the high reached 32.9 degrees - the hottest day in the first 10 days of May since 2001, the bureau said. The hottest day on record in the first 10 days of the month is May 5, 1939, when the mercury reached 35.2 degrees.

"Although the maximum temperature didn't break a record, it's rather unusual to have a long period of heat in early May," said Man Liping, a forecaster with the bureau.

Shanghai's summer usually arrives in late May.

(Shanghai Daily May 11, 2009)