I'm from Singapore and we have an annual rainy season (though we call it Monsoon Season). It lasts roughly from November to March due to the north-easterly moisture-laden winds from the South China Sea. From March to October, weaker south-westerly winds prevail but the wind passes over the much larger Indonesia island of Sumatra and loses much of its moisture and Singapore gets the leeward effect (thus the dry season). Having said that, I feel that the distinction between the wet and dry season has blurred. It could be a sultry week followed by a cooler and gusty week. I've even read on local news about a sofa being blown onto a busy road by a strong gust. Unbelievable!