Write a short passage in English to describe the climate characteristics of Chengdu all year round.

In Chengdu, basically, 1 1 is a bit gloomy from March to March, and it may rain and be a bit cold. The sky is almost always covered with a layer of gray like fog (but not fog), but the weather is warm enough for you to wear only one sweater outside. But in summer, the weather will never be gloomy. Most days of the week are sunny, and the blue sky is more obvious than in big cities with more pollution, but the weather is very humid and hot. It is well known that this is a humid area. In autumn, sometimes it will be rainy and rainy, and sometimes it will be fine weather in autumn. It is foggy and dry in winter, but it is not cold. It seldom snows there, only once or twice a year.