It is usually said that there are three seasons in Thailand: hot, very hot, and too darn hot! But seriously, there are indeed three seasons: the dry, or “cool” season, from November to February, the hot season, from March to June, and the rainy season, from July to October. The area of Cha-am is rather dry, the rainy season usually starts slowly and doesn’t last long. Sometimes Bangkok and Chumphon are flooded with rain, while Cha-am which is roughly half way from both stays dry as a desert.
The dry or cool season (November-February)
What is referred to as the “cool” season is only cool in the north (it can even be very cold). But as this website focuses on central and south Thailand, we will just say that December and January are not as hot as the other months of the year. It means that in January you can feel comfortable sleeping without air conditionning, and you may want to use hot water in your morning shower. In February it’s already getting hot again. The weather is usually very nice during this season, and it hardly rains (except at the very beginning of the season, in November), so it’s a very nice time to escape from Europe or America’s winter and visit Thailand.
As far as tourism and hotel rates are concerned, November to April is the high season (including the peak season from mid-December to mid-January).
The hot season (March-June)
It is always hot in Thailand, but March and April are even hotter. If it is your first visit to Thailand, do not underestimate the heat and the sun, and use some good protection (hat, sunglasses, cream). It is also very humid at that time, so physical activity can get you exhausted very fast. The sky is often cloudy, and it usually begins to rain in April-May.
The rainy season (July-October)
The rainy season is also very hot, and of course very humid! But it doesn’t rain all the time, and you can still enjoy a nice weather most days in the morning and beginning of the afternoon. Usually the sky starts to get cloudy in the afternoon, and it rains in the evenings. If you want to visit Thailand during western summer (July-August), you don’t need to worry too much about the rain. You can still get some tan on the beach in the morning, visit some places in the afternoon, and in the evening enjoy a drink somewhere watching the rain falling. You can even go swimming while it’s raining, if you want to know what it’s like!
May to October is the low touristic season, but with more activity from mid-July to mid-September.