In Haikou, it's still short-sleeved shorts and slippers. Hainan is an island on slippers, and Haikou is humid. I suggest you bring more short sleeves and slippers. If you want to live longer, you can go to the supermarket to buy some moisture-proof balls. Compared with inland cities, Haikou is dirty and humid, but it also has some beautiful scenery. Have a good time.