Hi Sue
There will be 23 people on your holiday and yes, you certainly will need to wrap up warm. It's likely to be below freezing in Beijing during the day, so packing thermals, scarves, gloves and so on is a very good idea.
We haven't appointed a tour manager for this trip yet but if you can write again in December, I should be able to let you know.
Kind regards,
Olly, your editor