El Nino Watch
Rotating storms that form over warm tropical seas. Rare on Samui but destructive; they mostly reach the Gulf of Thailand from October to January.
Hazards
"Tropical cyclone" covers tropical depressions, tropical storms and typhoons (the name used in the western Pacific). They bring strong winds, very heavy rain, big waves and storm surge.
Samui is hit rarely, but the risk-engine notes past examples: tropical storm Harriet (1962), typhoon Gay (1989) and storm Pabuk (January 2019). They mostly arrive from October to January, through the Gulf of Thailand.
Follow the TMD for official warnings and the DDPM (hotline 1784) for evacuation orders.