March in Ko Samui averages a daily high of 30.5°C with nights around 25.2°C. Expect roughly 4.3 wet days totalling 43.9mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Ko Samui is January–April.
Based on KO SAMUI, TH (14.7km), 1995–2024. 24 years of March data.