I'm planning a trip to Sapa, Vietnam with my family in early December. Would this be a good time to visit?

Winter time there!

I went once at that time of year and went on to drive the Dien Bien Phu loop. The weather was very mixed to say the least. It was very cold and even snowed on Fansipan. Though we did get some blue skies. We stayed in a variety of places form the Victoria Hotel in Sapa town to some very basic homestays . We enjoyed the trip but wouldn't do it again at that time of year. Indeed, I probably would bother with Sapa town again as I found it overrun with tourists and that was 25 plus years ago. I dread to think what its like now.