Hi, the downtown area is not very cold during Oct, so a thin sweater and jeans are okay. However, if you go to these scenic area, such as Emei Mountain and Jiuzhaigou, a warm coat is needed, especially at night.

Chengdu has various choice for accommodation, spaning from reasonable hostels to luxurious 5-star hotels. It is suggested that you look for on around the Jinli Street where some tour destinations assemble and a good nightlife spot~