• The rainy season starts in July with things getting gradually more wet as the year progresses. As a rule, the south of Thailand is generally wetter than the north. On the basis of this, it's probably reasonable to assume you will be seeing some showers during your trip.

However, Thailand has (along with the rest of the planet) been experiencing what can only be described as "weird weather", ie things are just not happening when they should! I was in Thailand in March this year and met some travellers in Chiang Rai who had abandoned the Phuket area to travel north because the weather was so awful down south - March is supposed to be "rain-free" according to the books.
Julia Knight