Hi Carol,
You are right, it will be cold. The average temperatures in January are:
Beijing -4 degrees C
Chengde -10/12 degrees C
Xian 0 degrees C
And if you choose to visit Harbin, it will be the coldest at -19 degrees C!
It will make a refreshing change from visiting hot places on holiday and as an added bonus January is the month with the least rainfall...a break from England! Apparently, if you start to get really cold, they sell traditional thick cotton army coats (Jun da yi) for less than 100 yuan, so keep a look out for those...would also be a great souvenir.
Regarding being a vegetarian, this will not be a problem. As in Britain and anywhere else you might visit, China will accommodate this. Just speak to your tour manager when you get there and I am sure he/she will be happy to advise any special requirements. But please dont worry, you may not be the only one.
You must be getting excited now, January is not far away. Soon it will be xmas and then China...it will fly by!
If I can help you with any other information, please let me know.
Warm wishes (you may need them in that weather!)
Cheryl, your editor