Wettest March on record followed by stormy start to April under inter-monsoon conditions
Singaporeans brace for more wet afternoons as thundery showers and gusty winds are expected throughout the first half of April 2025, according to the Meteorological Service Singapore (MSS).
With the Northeast Monsoon weakening, Singapore is transitioning into the inter-monsoon period. This shift is marked by unpredictable winds, increased lightning activity, and frequent thunderstorms. These seasonal shifts typically bring short but intense downpours in the afternoons and occasional morning storms.
In a weather advisory issued on April 1, MSS warned of moderate to heavy thundery showers expected over many parts of the island during most afternoons. Some of these storms may extend into the evening. The inter-monsoon period, which lasts until May, is also expected to bring increased lightning activity and unpredictable weather patterns.
Sumatra squalls may make brief but forceful appearances in the early mornings, causing intense rainfall and gusty winds. Overall, rainfall for the first two weeks of April is predicted to be above average, particularly in western and central Singapore. Daily maximum temperatures are projected to hover between 33°C and 34°C, and could spike to 35°C on certain days.
This forecast follows a particularly wet second half of March 2025, when heavy rainfall was observed across much of the island. March 2025 officially became Singapore’s wettest March since records began in 1980, with a total of 482.9mm of rain—eclipsing the 2004 record of 451mm. At Kallang, 216.8mm of rain fell in a single day on March 20 due to a strong monsoon surge.
The surge, brought on by intensified northeasterly winds over the South China Sea, was the third of its kind in 2025. It also drove temperatures down significantly, with lows hitting 21.9°C in Tuas South. According to MSS, Changi recorded rainfall 570 per cent above average for the second half of March.
With frequent downpours and occasional temperature drops, MSS advises residents to stay weather-aware, especially during the peak afternoon hours. The rainy spell may disrupt outdoor activities, increase travel delays, and contribute to slippery roads and flash floods in low-lying areas.
As Singapore transitions from monsoon to inter-monsoon, residents and visitors alike should prepare for afternoon storms and brief cold spells. The evolving weather conditions highlight the importance of staying alert and adapting plans around expected rainfall, especially during a period of such unusual precipitation levels.
Sources: Mothership (2025), The Straits Times (2025)
Keywords: Thundery Showers Singapore, Wettest March Record, Singapore April Rain, Monsoon Surge
