Chengdu Geography and climate from wiki

Chengdu is situated at the western edge of the Sichuan Basin. It is therefore sheltered from northwest winds from Siberia in winter by the Qinling Mountains to the north. The climate is mild and humid. The short winter is milder than in the Lower Yangtze because of the sheltering effect of the Qinling. Snow is rare but there are a few periods of frost each winter. The summer is longer, but not as hot as in cities such as Wuhan and Nanjing in the Lower Yangtse downstream. Average daytime highs are 10°C (49°F) in January and 30°C (85°F) in July. Rainfall is reliable year-round but peaks in the summer months.

Chengdu has one of the lowest sunshine totals in China (less sunshine annually than London), and most days are cloudy even if without rain. This is especially so in the winter months, when it is typically interminably grey and dreary. Spring (Mar-Apr) tends to be sunnier, warmer and drier than autumn (Oct-Nov).

from: http://en.wikipedia.org/wiki/Chengdu#Geography_and_climate

PS:Today is too busy...Tomorrow I will write some intresting things of Chengdu's geography more.