How is Huashan weather towards the end of December?

It may snow in December and very cold on the mountain. The roads may be wet and slippery so you are not advised to climb the mountain in such weather.

We stayed at West Peak hostel and our bottled water froze overnight. We were freezing cold. However, the next day met a few men that told us that they had just hiked up (partly in the dark). They told us it was nice and quiet and naturally not so cold once they got started. Not advisable unless you have someone to guide you.