In Singapore, the typical season for durian feasting is usually between June–August with a minor season from December to February.
The common durian (Durio zibethinus L.) and many tropical fruit trees require a dry spell of about one to two months for flowers to initiate and develop fully into fruits. In South East Asia where the durian is “The King of Fruits”, the durian production season is greatly influence by the north-east and south-west monsoons. In between the wet monsoons is the dry weather that triggers the matured durian trees to develop flower buds on healthy lateral branches. It usually takes about four weeks for the buds to develop fully into perfect flowers.
Durian flowers are borne in clusters of 3–10 flowers over a period of about two to four weeks during the dry season. The durian has a high rate of self-incompatibility and it is normal to get 20% to 25% fruit-set. Thus, cross-pollination is essential to obtaining good crops. Fruit development usually takes 95–130 days, depending on the cultivar. The tree must receive just enough water for proper fruit development.. Too much water will cause the tree to bear new leaves at the expense of the fruits. Under normal conditions, fruit ripening heralds the start of the rainy season.
The durian season in the major durian-growing countries of Thailand, West Malaysia and Indonesia generally peaks in the middle of the year around June-July.
Credit and information source: Durian Info