Increased Risk of Transboundary Haze with Drier Weather in Coming Months

Singapore, 2 August 2019 – The National Environment Agency’s (NEA) Meteorological Service Singapore (MSS) is forecasting drier-than-normal weather conditions in Singapore and the surrounding region, including Sumatra and Kalimantan, in the coming weeks. In recent days, persistent hotspot activities with smoke plumes have been observed in Riau and Jambi provinces in Sumatra and southern parts of Kalimantan. These conditions can lead to an escalation of hotspot activities and an increase in the risk of transboundary haze occurrence in Singapore and the surrounding region.

2      Since early July 2019, dry weather has been persisting over southern Sumatra and Kalimantan. Drier weather can be expected in the next three months (August to October), with monthly rainfall of up to 60% below average.

3     Singapore has likewise been experiencing dry and warm weather in recent weeks. The total rainfall recorded for July 2019 at the climate station in Changi is 92% below the long term average, breaking the record set in 1997 for the driest July in Singapore. July 2019 is also Singapore’s second warmest July on record, with an average temperature of 29.0°C.

Impact of the Indian Ocean Dipole

4     Neutral conditions (neither El Nino nor La Nina) currently prevail in the tropical Pacific Ocean, and are forecast to persist for the rest of the year. A key climate driver influencing the rainfall over Singapore and the surrounding region over the next few months is the Indian Ocean Dipole (IOD), which refers to the sustained change to the difference between sea surface temperatures (SSTs) of the tropical western and eastern Indian Ocean. The IOD varies between three phases – positive, negative and neutral. A positive (negative) phase occurs when cooler (warmer) SSTs develop in the eastern Indian Ocean, resulting in below (above) normal rainfall in the eastern Indian Ocean and the surrounding region. Each phase occurs every three to five years on average and typically lasts about six months.

5     The IOD is currently in its positive phase, which leads to drier weather over the areas adjacent to the eastern Indian Ocean, including Sumatra, Malaysia and Singapore. Major climate centres are predicting that the positive phase of the IOD is expected to persist over the coming months.

Risk of Transboundary Haze

6     Singapore may experience occasional occurrences of transboundary haze during the next few weeks to months. The likelihood of haze affecting Singapore is dependent on factors such as the proximity and extent of the fires, the direction and strength of the prevailing winds, and the incidence of rain.

7     MSS will continue to closely monitor the regional weather and haze situation, and provide updates when necessary. Updates on haze information are available on the MSS website at