Wild weather? Five things to note about Singapore's rainfall and heat in 2021

SINGAPORE: Wet, dry and hot - while that might sum up Singapore's weather, there were some extremes in 2021 with the return of La Nina.

The climate phenomenon, which occurs once every few years, typically brings more rain. 

And that was evident last year as Singapore saw its second-wettest year since 1980, according to the Meteorological Service Singapore on Friday (Jan 28) in its review of the year's weather. 

Here are five highlights from the report: 

1. WETTEST DAY

You might remember the flash floods in various parts of Singapore on Aug 24, most notably in the Bukit Timah area.

That Tuesday was the wettest day of 2021, with 247.22mm of daily total rainfall recorded at the Mandai station.

The Met Service called this a "remarkable" figure that far surpasses the previous August high of 181.8mm in 1983, recorded at Changi station. 

Flood risk warnings were issued for several locations on Aug 24, including the Upper Bukit Timah area where water seeped into a mall, Woodlands and Sunset Drive.

A week later on Aug 30, flood risk warnings were again issued for several areas after heavy rain fell across Singapore.

2. UNUSUAL AUGUST

August is usually among the drier months of the year - but not in 2021.

The wetter weather is due to a few factors, including La Nina conditions, said the Met Service.

"August 2021 saw well-above-average rainfall islandwide, with the Changi climate station recording nearly twice its long-term monthly average," it added.

3. SECOND-WETTEST JANUARY ON RECORD

The wettest month in 2021 was January.

It was, in fact, the second-wettest January for Singapore since rainfall records began in 1869 - exceeding the previous second-highest value of 634.5 mm recorded in 1918, more than a century ago.

The Met Service said the exceptionally wet and cool weather was due to a northeast monsoon surge, which brought continuous widespread rain over Singapore in the first weekend of the year.

4. WILD SWING? 

There was some respite from the rain the following month, which was a "very dry" February, said the Met Service.

It was the second driest February on record after February 2014, when climate stations recorded just 0.2mm of rainfall. 

The Changi climate station recorded just 1mm of rainfall for the whole of February 2021, while the highest daily total rainfall of only 46.9mm was recorded at Jurong West on Feb 11. 

It was also the second windiest February on record, with the Changi climate station recording an average daily wind speed of 13.1kmh, slightly behind the 13.7 kmh recorded in February 2014.

5. HOT HOT HOT

Found yourself dripping with perspiration more often? 

Despite the rain, 2021 was among the hottest years on record. The annual mean temperature last year was 27.9 degrees Celsius, 0.1 degrees Celsius above the long-term average of 27.8 degrees Celsius. 

This made 2021 match previous years such as 2018, 2014 and 2009 as the country’s 10th warmest year on record. 

It matches global trends reported by the World Meteorological Organization, the Met Service said, noting that 2021 is likely to be between the fifth and seventh warmest year on record.

It could perhaps be warmer if not for La Nina conditions, which helped moderate Singapore's overall temperature in 2021.

With more extreme weather events expected due to climate change, people will have to get into the habit of checking the daily weather forecast and adjust their plans accordingly, Minister for Sustainability and the Environment Grace Fu said in August last year.

“For far too long, Singaporeans have grown used to our weather, as we think the weather doesn't change very much," she said. "But increasingly, we need to build the habit of checking weather forecasts, checking weather advisories to go about our daily lives."

Ms Fu added that Singapore needs to plan for climate change and ways to mitigate its effects.