This is a tough question as all weather questions are.
November on the Andaman side is the supposed start of the better weather.
November for Samui is in the wet season.November for Samui is normally one of the months for heaviest rainfall.Now what that rainfall consists of is anybodies guess.People have been to Samui in November will report just heavy thunderstorms & the majority of the day is ok.Others will say they have been in November & it`s rained for days on end.For the record last November wasn`t too bad.
A couple of years ago the rain hung around on the Andaman side till around xmas.
The weather patterns this year for Samui especially, have been a little off kilter compared to other years so who knows what November is likely to bring.
If I was a gambling man i`d have something on Phuket for the better weather.
