Since Sentosa is a little off Singapore, the resort island’s weather is similar to its parent city. Being a year round tourist destination, Sentosa is accessible to tourists for most time of the year; there’s not much to consider weather wise while planning a trip here.
Summers: The best time to visit Sentosa is between the months of June to July. Most of the schools in South Asia have holidays and families plan trips the most during these months. The temperature is fairly constant throughout these months with warm sunny days and cool nights. Being on the Equator the weather is pretty stable year round with the average low of 20 degree Celsius to average high of 30 degree Celsius.
Winters: Months of November and December are good for outdoor activities without getting dehydrated or feeling the pangs of heat. At this time of the year, the weather is pleasant and ideal for sightseeing and enjoying the various activities Sentosa has to offer.
Monsoon: Having no distinctive seasons such as summers and winters, the island does however face monsoons starting December onwards till January end. February and March, although not completely wet, do face a few rainy days.
So, the best time to visit Sentosa is between June to July and October to December.