People head to Singapore all year round as the temperature averages at about 27 degrees. It is usually always warm, but sometimes wetter and more humid than others. The cooler months are October - January. It can rain anytime but November, December and January can often have the most rainfall. There is no distinct wet or dry season and showers are usually sudden and heavy rather than constant rainfall.

I hope that helps a little.

from june-august in summer vacations