Singapore is unlikely to see a repeat of the prolonged rain and cooler conditions experienced in early January 2025, as no monsoon surge is expected in the coming week, the Meteorological Service Singapore (MSS) said.
This comes despite concerns in the region after Malaysia warned of a potential monsoon surge in early January 2026, which has already led to flooding and the evacuation of more than 1,000 people in parts of Sarawak.
A monsoon surge is a recurring weather phenomenon during the wet phase of the north-east monsoon season, which typically spans December and January.
Singapore usually experiences two to four such events during this period, with each episode lasting several days. These surges are known to bring persistent rainfall, gusty winds and lower temperatures.
The phenomenon occurs when cold, dry air from winter regions such as Central Asia flows southwards over the warm waters of the South China Sea. As the air mass travels, it gathers moisture, resulting in widespread rain and unsettled weather conditions across affected areas, including Singapore.
The impact of such events was evident during the first monsoon surge of 2025 on January 10, when prolonged rainfall led to flooding in Jalan Seaview in Mountbatten for nearly three hours. That four-day spell of heavy rain also disrupted flights and dampened business at Chinese New Year bazaars. The flooding was exacerbated by high tides of up to 2.8m coinciding with intense rainfall, with total precipitation over January 10 and 11 surpassing the month's average.
High tides are again expected this week, according to checks on the National Environment Agency's website.
Afternoon tides are forecast to exceed 3m on several days, reaching up to 3.3m at times. Around noon on January 5, a high tide of nearly 4m was recorded at Sungei Buloh Wetland Reserve. However, MSS noted that without a monsoon surge, the likelihood of widespread flooding remains low as overall rainfall is expected to be reduced.
In its fortnightly weather outlook issued on January 2, MSS said rainfall in the first half of January is forecast to be below average over most parts of Singapore.
An MSS spokesperson explained that potential monsoon surges can usually be detected several days in advance through weather models that track the build-up of high pressure over northern Asia and stronger winds over the South China Sea.
To forecast these events, MSS scientists rely on a combination of real-time weather observations and computer models that simulate atmospheric processes.
During the Northern Hemisphere winter, cold conditions cause air over land to sink, forming large high-pressure systems over regions such as Siberia and China. When these systems intensify, they can release bursts of cold air that surge southwards.
As these cold air masses move over the warm sea, they may interact with low-pressure systems near Singapore, forcing air to rise and form dense cloud clusters. This interaction can significantly intensify rainfall. As a surge approaches, MSS increasingly depends on satellite imagery, radar data and weather station readings to monitor its development.
Monsoon surges are generally easier to predict than localised thunderstorms because of their large scale. This allows forecasters to provide warnings at least a day in advance when possible. However, predicting the strength of each event remains challenging.
For example, the second monsoon surge in January 2025, which occurred between January 17 and 19, turned out to be milder and shorter than expected, bringing intermittent showers rather than continuous heavy rain.
Communicating forecasts clearly remains a challenge due to uncertainties in intensity and timing, the MSS spokesperson said. Even slight shifts in the position or movement of strong winds and cloud clusters can significantly alter local weather conditions.
As a result, Singapore may sometimes experience relatively fair weather while neighbouring regions, such as parts of Malaysia, bear the brunt of heavy rain and flooding. MSS noted that north-east monsoon surges can affect a wide area, from northern Peninsular Malaysia down to Singapore, but the most severe impacts do not always occur in the same location.
