February has its own peculiarity - Chinese New Year, which depends on the lunar cycle, but usually falls in the middle of the month. If you have already finally decided on the days of rest on the island, then book your accommodation and travel in advance, since the closer the month approaches, the less free rooms remain in hotels. 

If you have only a few days to explore Koh Chang, you should not worry about the weather in February - the island will be waiting in company with the blazing sun and the quiet sound of the surf.