Apparently a lot of the crappy weather Hainan has had recently has been due to cloud seeding. They want it to be cooler this year. It is an interesting angle on the whole global warming phenomenon. China uses it because Hainan apparently doesn’t have enough water from other sources. But they also plan to use it during the 2008 Olympics to clear the air (since Beijing is too polluted by Olympic Committee standards).
While it may have some benefits, the temperature drop is not one of them. Last year, it was around 37 degrees C during the day. This year, 25 degrees. Colder at night. Many of my classmates came to Hainan to enjoy the weather, and perhaps they need good weather. It seems like over half the students are "under the weather."