we went to Bangkok 13th June and then on to Koh Samui 16th June for a week this year. The weather was generally good. Very humid in Bangkok but very warm with occasional cloud cover. Koh Samui was lovely, more sunshine until the last couple of days when we had some rain and cloud cover, but it was still very warm.

I was in BKK this May for 2 weeks with the middle weekend down on Koh Samet... The monsoon was early this year and rain was heavy at times. However even if most of the day was cloudy the rain was in relatively short but hard bursts. You won't get as much sun as say, in December/January and it will be humid but then again for most of us Non-Thais it is always humid there!!! I still got a tan though!!!