Widespread thundery showers and gusty winds are expected in the second half of September 2025 in the pre-dawn and morning in Singapore, according to a forecast by Meteorological Service Singapore on Sep. 16.
This is due to persisting Southwest Monsoon conditions across the country and the surrounding region.
Fewer dry days due to prevailing Monsoon
In their advisory, MSS said that the conditions will bring winds blowing mainly from the southeast or southwest.
During this period, Sumatra squalls are likely to bring widespread thundery showers and gusty winds in the pre-dawn and morning on several days.
Localised, short-lived thundery showers are also expected over parts of the island on some afternoons.
A few dry days may occur.
Overall, total rainfall for the second half of September 2025 is forecast to be near average across most areas.
Daily temperatures are expected to range between 24 degrees Celsius and 33 degrees Celsius on most days.
While thundery showers are anticipated on most days, the daily maximum temperature could rise slightly above 34 degrees Celsius on a few occasions.
Higher rainfall in first half of September
In the first half of September 2025, Southwest Monsoon conditions prevailed over the region with low-level winds blowing mainly from the southeast or southwest.
Localised, short-lived thundery showers developed over parts of the island on several days due to the Sumatra squalls.
Pre-dawn and morning thundery showers across Singapore also occurred on multiple occasions.
On Sep. 5, one such squall produced widespread thundery showers and gusty winds in the morning.
The highest daily total for the first half of September 2025 was recorded at the Sarimbun Reservoir area, with 102.6mm of rainfall that day.
The rainy and cloudy weather during this period kept conditions relatively cool on several days.
Four days in the fortnight registered daily maximum temperatures below 30 degrees Celsius while the highest daily maximum of 33.8 degrees Celsius was observed at Admiralty on Sep. 3.
Overall, rainfall was significantly above average across Singapore in the first half of September 2025.
Seletar recorded 248 per cent above-average rainfall, while Paya Lebar registered 73 per cent above average.
Top photo via Unsplash
