August in Koh Lanta Yai is the windiest month of the year. In August, the weather in Koh Lanta Yai is typically hot. Average daily high temperature in August is about 28 degrees above zero. On average, Koh Lanta Yai has 25 rainy, 5 cloudy, and 1 partly cloudy day in August. The rains are usually heavy. August as well as April, May, June, and July is considered the most uncomfortable time to visit Koh Lanta Yai.