Weather & Climate in Manado
Like other regions in Indonesia, North Sulawesi has a typical equatorial climate with two seasons: rainy and dry. Starting in September, cool Northwesterly winds pick up moisture while crossing the South China Sea and arrive in the Sulawesi Sea about November. The wet season lasts from about November to March, but it is usually less pronounced than in many other parts of Southeast Asia and thus not really a serious concern in North Sulawesi. Hence you can visit Manado year round! You are practically free to consider your own schedules, and perhaps avoid the holiday crowds..
Weather for Divers
Diving is possible all the year round. Bunaken and the Manado Bay are very sheltered, the sea is seldom rough. Visibility is generally over 20 m (up to 40 m). This is what happen normally in dry season between May to October. The wet season is from November to April has little influence on the visibility at Bunaken Islands whereas it may affect visibility more in Manado Bay. The diving is still possible to do. But the sea is often rough and sometimes danger for sailing especially in December and January. Please avoid this month. Can go diving but not Fun. West winds often comes at these months and make diving at the west part of Bunaken island not so good, safe and comfortable cause of the wave. If this is happen, most divers do diving at the east part of Bunaken island. So best time to come in North Sulawesi for diving in Bunaken itself is from May to October. But if you plan to come dive at Lembeh strait, North Sulawesi, it is the best time for wet season. Why? cause most divers are recommend so. They said most critters coming out at wet season at Lembeh Strait