Slight haze may affect Singapore on Tuesday, likelihood to reduce towards Wednesday due to rain forecast: NEA

SINGAPORE: There is a chance of slight haze affecting Singapore on Tuesday (Oct 17) with a reduced likelihood of it towards Wednesday due to more rain forecast, the National Environment Agency (NEA) said on Monday.

Some showers are expected over Singapore on Tuesday while continued dry weather is forecast over the surrounding region, said NEA in its daily haze advisory.

"The prevailing winds are expected to blow from the southeast, and occasionally from the south to southwest, with a chance of slight haze affecting Singapore."

The 24-hour Pollutant Standards Index (PSI) for Singapore is forecast to be in the moderate range, NEA added.

The likelihood of transboundary haze affecting Singapore "is expected to reduce towards Wednesday" as shower activities are forecast to return to the surrounding region.

Dry conditions persisted over most parts of the surrounding region on Monday.

A total of 285 hotspots were detected mostly in the southern and central parts of Sumatra on Monday, up from the 24 hotspots detected on Sunday.

As of 6pm on Monday, 1-hour PM2.5 concentration readings were in the normal range.

The PSI, meanwhile, ranged from 54 to 72, which is in the moderate range. 

The skies have been mostly clear since Oct 7 when air quality fell into the unhealthy range for the first time since 2019.

Smoke from forest fires in central and Southern Sumatra was blown by winds towards Singapore on Oct 7 and Oct 8, which resulted in hazy conditions.

The highest 24-hour PSI of 123 was recorded in the eastern part of Singapore between 8pm and 9pm on Oct 7.

But rain over Singapore and the surrounding region last week lowered the likelihood of haze.

More showers are also forecast for southern Southeast Asia in the coming two weeks, which may improve the situation and reduce the chance of transboundary haze affecting Singapore.

"The chance of the 24-hour PSI reaching the unhealthy range in Singapore is low for the coming fortnight,"   the Meteorological Service Singapore (Met Service) said in its fortnightly weather advisory on Monday.