Koh Tao normally have fairly stable weather almost all year round.
As Koh Tao is located on the east coast, the island has another rainy season than the West Coast, therefore the most rain falls in October and November.
The remaining months may have rain once in a while.
March and April are the driest months and June to August the warmest. December to February are the coolest months.
But as I said this is how it usually has been, but this year the weather gods has been crazy as you all have read and heard, there has been major flooding throughout southern Thailand including Koh Tao. And this has occurred in March and April that will be the driest and warmest months …
More On Koh Tao’s weather will be found on the Zoover’s website.