2021 was an exceptionally wet year, and the period from 2012 to 2021 was Singapore’s warmest decade on record.
The National Environment Agency’s (NEA) Meteorological Service Singapore (MSS) shared the findings in the "2021 Climate and Weather: The Year in Review" report, released on Jan. 28.
1. Second wettest year since 1980
2021 saw significantly wetter-than-average conditions.
Islandwide stations measured an average annual total rainfall that was 25 per cent higher than the long-term annual average.
At the Changi climate station, it was 33 per cent above the long-term annual average.
Most months in 2021 experienced above-average rainfall.
Almost all of these wetter months also ranked within the top 10 wettest for the respective months in the past 40 years, based on the islandwide average.
In January, a total rainfall of 692.8 mm was recorded at Changi climate station, which was the highest in the past 100 years for the month.
2. 2012 to 2021 is the warmest decade on record
Similar to global trends, the last 10 years in Singapore have been the warmest decade on record.
This is despite La Nina conditions present during much of 2021, which contributed to higher-than-normal rainfall in the year and helped to moderate Singapore’s overall temperature in 2021.
The mean temperature from 2012 to 2021 was 27.97°C, some 0.02°C higher than the previous record from 2010 to 2019.
2021's annual mean temperature was 27.9°C, which is 0.1°C above the long-term average of 27.8°C.
This ranks 2021 as Singapore’s joint 10th warmest year on record, along with 2018, 2014, 2009, and 2004.
Globally, 2021 is expected to be between the fifth and seventh warmest year on record.
3. A very wet January
The first half of January was exceptionally wet and cool due to a Northeast Monsoon surge, which brought continuous widespread rain over Singapore.
The monthly rainfall recorded at the Changi climate station for January 2021 was 692.8mm, with 648.4 mm recorded in the first fortnight alone.
The highest daily total rainfall of 210.6 mm was recorded at the Changi climate station on Jan. 2, 2021.
This makes January 2021 the second wettest January since rainfall records began in 1869, exceeding the previous second highest value of 634.5 mm recorded in 1918.
4. Followed by a dry and windy February
February 2021 was the second driest and windiest February on record after February 2014.
The highest daily total rainfall for the month was just 46.9 mm at Jurong West on Feb. 11.
Meanwhile, the Changi climate station recorded a mere 1.0 mm of rainfall for the entire month.
Changi climate station also recorded an average daily wind speed of 13.1 km/h.
It was the second windiest February since continuous wind records commenced in 1984, behind the previous record of 13.7 km/h.
5. Unseasonably wet August
August saw well-above average rainfall islandwide, with the Changi climate station recording nearly twice its long-term monthly average.
Exceptionally heavy rain fell on Aug. 20 and Aug. 24, which led to flash floods in some areas.
The wettest day of 2021 was recorded on Aug. 24, which is usually among the drier months of the year.
A remarkable 247.2 mm of rain was recorded at Mandai station on that day, setting a record for the highest daily total rainfall for August, and far surpassing the previous high of 181.8 mm at Changi on Aug. 22 1983.
Top image by PUB/Facebook.