The Meteorological Services' three-day outlook predicts rain until Wednesday.

Morning showers with thunder are expected on Monday, while those heading out should be prepared for late morning and early afternoon showers with thunder over the next two days as well.

August, which started out as a drier than usual month, is now likely to surpass the usual average rainfall for the month of August.

In the first two weeks of this month, more than three quarters of the island experienced below average rainfalls.

The eastern parts of Singapore around Changi and Pulau Tekong received the highest rainfall during that period, while the lowest rainfall was in the northern and southern parts of the island around Kranji and the City areas.

But in the last two weeks of August, short duration showers with thunder are expected on seven or eight days. The National Environment Agency's website said it is due to prevailing South-west Monsoon conditions.

The Met Service's forecast now is that in most parts of Singapore, the total rainfall for this month will exceed the August average rainfall of 175.1mm.