In April, the weather in Koh Lanta Yai is typically hot. Average daily high temperature in April is about 29 degrees above zero. On average, Koh Lanta Yai has 22 rainy, 4 partly cloudy, 3 sunny, and 1 cloudy day in April. The rains are usually heavy. April as well as May, June, July, and August is considered the most uncomfortable time to visit Koh Lanta Yai.