The south-west monsoon is established by June, the offshore on the east coast is reliable, and the swell that has been building since May has enough size to run the full length of the Main Point at Arugam Bay. That is the wave that made the name. It breaks over reef, and it is the only one of the four points with a crowd on it.
The other three are the reason to stay rather than visit. Whiskey Point is north of the bay, Peanut Farm and Elephant Rock further along the coast, and Elephant Rock is a right-hand point gentle enough for a beginner on the days it has enough swell. Almost nobody rides past the first point they reach, and that is the whole opportunity: twelve kilometres of coast, four waves, and one of them absorbing everybody. A scooter or a tuk-tuk turns a week here into four options instead of one.
The rest of the island is on the other schedule, and it catches people out every year. The south coast is wet and onshore, Weligama has almost no clean day in a typical week, and the camps around it are closed or half empty. Anyone landing in Colombo planning to drive south has booked the wrong month. Arugam Bay is six to eight hours from the airport across the interior, so treat the arrival as a travel day.
What June buys is the last quiet month of the east coast season. The town is running, the bars are open, somebody arriving alone is not alone by the first evening, and crowds and prices are still a step below July and August, when the main street fills with surfers from everywhere. The sea is 28°C and a rash vest is the whole kit. If you already surf, June is the month to have the points with room on them; if you are learning, read the beginner note first, because the gentle breaks rarely get enough swell yet.

