As Thailand is located in Tropical monsoon climate zone, it enjoys a tropical monsoon climate with the annual average temperature of above 18? and the yearly precipitation of about 1000 mm. From November till February, the weather is dry and cool under the influence of northeast monsoon. The hottest period falls from March to May with temperature ranging from 40? to 42?. The rainy season falls from July to September under the influence of southwest monsoon. From October till December, there are occasional tropical cyclones from South China Sea via Indo-China Peninsula and blow the east of Thailand. But there are very few and weak tropical cyclones formed in the Gulf of Siam.