The central part of the island is an almost uninhabitable jungle mountain, Khao Pom, peaking at 635 m. The various lowland areas are connected together by a single 51 km road, running mostly along the coast to encircle the bulk of the island.
Each of Samui's primary beaches is now also nominally considered as a small town, due to the number of hotels, restaurants and nightlife that have sprung up in recent years.
Ko Samui, being in Surat Thani Province, has essentially two seasons; warm and tropical most of the year, with a short rainy season. Unlike Phuket and most of the rest of Southern Thailand which has a 6-month rainy season between May and November, Samui's weather is relatively dry for the vast majority of the year, with the rainy season being primarily confined to November. For the rest of the year, since the weather is tropical, when it does rain, it usually doesn’t last long; rain showers of 20–60 minutes are typical.
With this broad mixture of cultures, Ko Samui is always celebrating some tradition or another, including some western ones.
After the exploding tourism in Ko Samui there has been a growth in building resorts, bungalows and luxury private villas on the island. This economic growth has led many businessmen from all over the world to invest in Ko Samui. With over 260 resorts and bungalows in Samui, counting from the end of year 2009, it has become Thailand's second largest resort business behind Bangkok and surpassing Phuket.
Buffalo Fighting Festival One of the best-known festivals on Ko Samui is its Buffalo Fighting Festival, which is held on special occasions such as New Years Day and Songkran. Unlike Spanish bull-fighting, the fighting on Ko Samui is fairly harmless. The fighting season varies according to some ancient customs and ceremonies. The buffalo are beautifully decorated with ribbons and gold-painted leaves. Before the contest which lasts just two rounds, monks spray them with holy water. The winning owner typically takes home millions of baht in prize money.
Ten Stars Samui Art Party A recurring cultural event bringing together art lovers, local Thai and international artists and their new, original artworks. These bi-monthly events, hosted at various high-end resorts and other 5-star venues on the island, focus on building the art community on Ko Samui with presentations by featured artists.
Bowling Championship This is an annual bowling event held in May every year.
Avis Samui Tennis Open The annual amateur tennis tournament held in July.
Samui Regatta The Samui Regatta is a sailing tournament, held every year. The tournament is internationally known and competitors come from as far away as Australia, Singapore, Japan and China. This event, for boats of all sizes and shapes, began in 2002.