We would plan to visit chengdu during Christmas, is it good timing?

To be honest, I do not think it is a good time. It will be cold and wet during that time. The average temperature during that time is around 4 to 10C. Most of the days are cloudy.

It's quite difficult to say it's good or bad. The focus is your aim. Which places do you want to go? If you come here to see pandas, it's good as you will see them playing outside and have sunbath in their playground. Or if you want to go the Mt. Emei, it's not bad too. You may see the clouds sea and beautiful sunrise at Golden Peak. And of course, snows there is so good, too.