I will be gtg HK from 16 Dec to 20 Dec. So what kind of clothing is good for kids.. Thick jackets?

It is dry and cool at that time with an average temperature of 17 C (63 F). The temperature then is changeable – when a cold front comes, the cold and dry north wind brings a sudden drop in temperature down to less than 10 C (50 F) suddenly; when it clears, the temperature will again rise up to 20 C (68 F) or above. Thus, you need to prepare long-sleeved T-shirts, wool sweater, jacket plus warm coat this time for your baby.