- Monsoon Update
(Updated on 19 August 2019)
The prevailing Southwest Monsoon conditions in the region are forecast to last till October 2019. During this period, the low level winds are forecast to blow mostly from the southeast or southwest, and on occasion, blow from the west.
Singapore and the surrounding region can expect a drier and warmer-than-usual Southwest Monsoon season this year. This can be partly attributed to the prevailing positive phase of the Indian Ocean Dipole (IOD). A positive phase of IOD occurs when cooler sea surface temperatures develop in the eastern tropical Indian Ocean, bringing drier than usual condition in the eastern Indian Ocean and most of the southern ASEAN region, including Indonesia, Malaysia and Singapore. Major climate centres are predicting that the positive phase of the IOD is expected to persist over the coming months.
With drier and warmer weather forecast to persist for the rest of the Southwest Monsoon season, we may see an escalation of hotspot activities over the southern ASEAN region. This would increase the risk of occurrence of transboundary haze in the region. The impact of the smoke haze on Singapore is dependent on factors such as the proximity and extent of the fires, the strength and direction of the prevailing winds, and the incidence and amount of rain.
Despite drier than usual weather, short-duration thundery showers can still be expected over Singapore mostly in the late morning and early afternoon on some days in the coming months (August-September-October). Occasionally, presence of low pressure systems in the nearby seas could trigger the eastward passage of Sumatra squalls from Sumatra or the Strait of Malacca and bring widespread thundery showers accompanied with gusty winds to Singapore between the predawn hours and morning.
The rest of this Southwest Monsoon season is expected to be warm. On most days, the daily temperature over Singapore is forecast to range between 25°C and 34°C, with highs of around 35°C on some days. Some nights can be generally warm with daily minimum temperatures above 26°C over most parts of the island. The minimum temperature in the southern and eastern coastal areas of Singapore can be around 28°C on some nights, when prevailing winds blowing from the southeast bring in warm and humid air from the surrounding seas.
For the period August-September-October 2019, significantly below normal rainfall and well-above normal temperatures are predicted over Singapore and the surrounding equatorial Southeast Asia region.
The long-term rainfall and temperature statistics for August, September and October at our climate station are shown in Table 1.
|Average Monthly Rainfall Total (mm)||148.9||156.5||154.6|
|Average number of rain days (Days with 0.2mm or more of rainfall)||14||13||15|
|Average Daily Maximum Temperature (°C)||31.4||31.4||31.7|
|Average Daily Minimum Temperature (°C)||25.0||24.8||24.7|
Table 1: Long-term rainfall and temperature statistics for August, September and October
For the latest weather forecast, including heavy rain warnings, please visit our MSS website (www.weather.gov.sg), NEA website (www.nea.gov.sg), download the myENV app., Weather@SG app, weather information hotline at 65427788, through following NEA’s twitter via @NEAsg or from radio broadcasts.
 The Indian Ocean Dipole (IOD) 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. More information on the IOD can be found at www.weather.gov.sg/LEARN_climate/.
 Based on 30-yr climatological reference period (1981- 2010)