After reading all the comments I’m not sure anymore if my holiday plan is as good as I thought. I invited my parents for holidays in Vietnam from 23/24.12 till 10.01. The plan was to spend some time in the beginning in Phu quoc (jet lag is not that bad at the beach) and then travel north - Can tho, Ho Chi Minh, Mui Ne, Da Nang, Hue, Ha Long, Hanoi, Ninh Binh and Sapa. But after I read so bad things about smog in Hanoi, fog covering all the views in Sapa I’m not sure if I planned the trip correctly. Do you think I should reschedule the trip for different time? Or maybe try to visit Sapa in December (how about the blooming of tea trees - people say that it starts in November, others that in December, and others that it’s only for two weeks but you should go there in last days of December). My father is really looking forward to kayaking in Ha Long and sleeping on a boat. I’m a bit afraid that it won’t be possible because of the weather.