October is the best time to visit Beijing.
Long sleeved T-shirt and coat will be ok.

The weather of Oct is nice in Beijing. That's good for touring and business trip. The sleeved T-shirts, knitted garments, dust coat are all fine. But sometimes it is wendy in Beijing in Oct, you need to wear more than that.

Last year i was in china during october, it was very pleasant weather. Nights are sometimes somewhat chilly so take light woolen clothing. Comfortable casual will do and if any business meetings, then take appropiate clothing. Even we are visiting china from 22 oct to 2nd nov in Beijing and shanghai.