Prices, Weather, Crowd in Sanya

Well, it will be a nice season for travel. Th weather will be cool and comfortable, with the average temperature of 20-22C. No need to worry about the cool water! You can surely go to the seashore and enjoy yourself by swimming, especially between 11:00-15:00. Otherwise, you may feel the water being a little cold. Generally, during that time, it will be the high travel season, so maybe a lot travelers there, but not that crowded.
As for the meal price, you may need around 100RMB for three persons' meal.
For 4 days trip per person, you'd better prepare about 2,000RMB or more in case including the accommodation fee.

Hi Cksh, being a local citizen here more than 20 years, I am believe it is the best time to visit SY, maybe you can't image how people can swim in the ocean in winter, but you can experience yourself there at that time, and this is a little crowded as many visitors come from other China city and other countries's visitors.
the food,drink's price is the same as other time as controlled by local government, the exact price depended on what you eat and taste, for the normal local food, as normal, RMB50/person is enough for local people, if you want to taste seafood about RMB400/4 peoples, but the hotel at this time is about 3 ~ 4 times than other season, seafront hotel need about RMB600/per twim room,the snorkerlling is from RMB300 ~ RMB800/person, welcome to SY