Basically, Thailand has three seasons: a dry and hot season (from November until February), a very hot season (from March until the end of April; the weather is still dry, but very hot, and doing sightseeing tours may be uncomfortable) and a wet and hot season (this is the monsoon season from May to the end of October). Koh Samui, however, is a little bit different from the rest of Thailand - the islands in the southwest of the Gulf of Siam have climate of their own. the best time for travelling to Ko Samui are the months from March to September. The rainy season starts in October; most rainfalls occur in November.

Clothing You should dress for a tropical climate: cotton or silk clothes are most comfortable (linen is too heavy). Exposing too much of your skin will not only earn you a sunburn, but is also frowned at by the locals. Not matter, how hot is is, gentlemen must wear long pants in urban areas. For ladies, pants are also o.k., or you can wear a skirt or a dress that covers the knee. (Loose-fitting dresses are probably most comfortable). Sleeveless shirts or sweaters should also be avoided.  The rules  are even more strict for temple visits. Health

The standard of hygiene in first-class hotels is in general o.k., but you should not drink the tap water (though it can be used for teeth brushing). The better hotels provide bottled drinking water for free. You should be careful with the food from foodstalls or in simple restaurants. Eat only things that have been thoroughly cooked and are served really hot. The large amounts of chili that are part of nearly every Thai dish may have a disinfecting effect, but you should not rely on this! (The people themselves are nearly always neat and clean, but sometimes they use dirty water for dishwashing, etc.) Vaccinations against tetanus, hepatitis, and salmonella infections are generally advisable.

Safety

Thailand is generally considered a safe country and for tourists, Ko Samui is very safe place with no open violence in the streets. There is probably criminality, but it is unlikely that you will encounter it. The worst that could happen to you is probably that you get pickpocketed or that a tout tries to take you to a shopping center. These people often wait in front of temples or museums and tell you that they are closed. Guess what they suggest you should do instead? Right, visit a jewellery shop - or a handicraft store... Just ignore them.  If the temple happens to be really closed, you can come back and get a taxi or a songthaew then. Always refuse when somebody offers you a free tour at tourist attractions As everywhere, of course, it is better to avoid carrying large amounts of cash; credit cards or traveller`s cheques are preferable.