September is the last month of the south-west monsoon, and on the east coast it behaves like the tail of a good season. The swell is less frequent than in July and August and the offshore is less reliable towards the end of the month, but the days that work are the same days, on points that are suddenly empty.
The European holidays are over and Arugam Bay empties out in the first week, so a September trip is the same coast at a fraction of the crowd. It is the value month of the east season, and the last before the island spends October between monsoons. The water is at 28°C.

