Thailand has a very tropical climate with three informal seasons: cool, hot, and rainy. Almost all of Thailand with exception of the mountain region is very humid. Temperatures range from 8 degrees Celsius at night to a scorching 38 degrees Celsius or higher in the day during the hottest months. Summer, starting around mid-February to mid May. Most tourists visited Thailand in this season. The rainy season begins around mid-May to mid-October.