Thailand is ideal for golf, no matter what time of year. The country has three distinct seasons: cool (November – February), hot (March – June) and rainy (July – October), with temperatures soaring up to as much as 35 degrees Celsius or more in the hottest month of April.
Golf is fine during the rainy season as it seldom rains for more than a couple of hours at a time, usually in the evening or night. In the north of Thailand, the cool season can be decidedly chilly – you might need a sweater, especially in highland areas – while in the rest of the country the cool season is still hot by Western standards, certainly over 20 degrees. The south tends to get rain throughout the year, usually in the afternoon or evening.
Probably the best time to take to the links is in the early morning or late afternoon, when the sun is not quite so scorching. Some courses also offer floodlighting, so you can even enjoy a round after sunset.