Hi Heather,
I did China with TS last month & it is, so far as I can remember, the only trip where I have worn shorts as it was hot and a scarf as it was cold (although not at the same time) on the same trip!
We started off mid October in Shanghai & then a Yangtze cruise and that was shorts and polo shirt weather. It was comfortable for the pandas but we met rain for the terracotta army (although the exhibits are indoors) before heading for Beijing, where the scarf came out, and where there was black ice on the shaded parts of the Great Wall.
I looked at a weather site before I went which suggested 60F all the way round but don't believe all you see on the web! (Reviews here excepted of course!) but having a pal who had been there before I was warned I might find it cold in Beijing.
Layers are the order of the day.
It was a great trip and you are sure to have a great time - whatever the weather is doing.
Ian