SINGAPORE - The first two weeks of June are expected to be as wet, warm and humid as it was in the last two weeks of May, said the Meteorological Service Singapore in a statement on Friday (May 31).
With strong day-time heating of land areas, thundery showers are expected mostly in the late morning and early afternoon on six to eight days of the first fortnight of June, said the weatherman.
On two to three days during that period, Sumatra squalls moving from the Strait of Malacca to the South China Sea could track over Singapore and bring widespread thundery showers and occasional gusty winds in the morning.
The overall rainfall for the first half of June is likely to be above normal for most parts of Singapore.
The prevailing light and variable winds over Singapore and the surrounding region are also forecast to strengthen and blow from the south-east or south-west, signalling the end of the inter-monsoon period and the start of the south-west monsoon season.
The south-west monsoon season typically extends into September and is generally drier compared to other times of the year, said the MSS.
As the south-west monsoon season sets in, more warm and humid nights can be expected.
Warm nights typically occur when the prevailing winds blow from the south-east and bring warm, humid air from the sea over the land.
The daily temperature on most days is forecast to range between 25 deg C and 33 deg C.
Minimum temperatures at night can go up to 28 deg C on some days.
In May, inter-monsoon conditions prevailed in Singapore and the surrounding region.
The Republic experienced thundery showers in the late morning and afternoon on most days due to convergence of winds over Singapore and the surrounding vicinity.
On several days, particularly in the second week, there were widespread thundery showers as Sumatra squalls passed over Singapore.
May is one of the warmest months of the year, said the MSS.
During the month, the highest daily maximum temperature across the island was at least 34 deg C on more than half of the number of days in May.
The highest daily maximum temperature recorded was 35 deg C while the lowest was 20.8 deg C.
Using data collected from the climate station in Changi up to Thursday (May 30), the mean monthly temperature of 29.3 deg C for May 2019 is set to tie with May 1997 and 2016 as the second warmest May in Singapore since temperature records started in 1929.
May 2019's mean daily minimum temperature of 26.5 deg C is also likely to tie the record high set in May 2003 and 2016.
Slightly less than half of Singapore received above average rainfall in May this year, with most of the rain falling over the south-west of Singapore.