CNA – Although Singapore experienced its hottest May day on record earlier this month, with the mercury hitting 36.7 degrees Celsius at Admiralty, the country is not experiencing a heatwave, said the Meteorological Service Singapore yesterday.
A heatwave occurs when the daily maximum temperature is at least 35 degrees Celsius on three consecutive days, with the daily mean temperature throughout the period being at least 29 degrees Celsius, said the Met Service.
“We are not currently experiencing a heatwave,” said a spokesperson. “We are however expecting the second half of May 2022 to continue to be warm and drier compared to the first half of the month.” The warm weather is not unexpected, experts told CNA, noting that April to May is usually the hottest period of the year.
“May is just past the spring equinox which means that the sun is almost directly overhead at noon in Singapore. Being within the inter-monsoon period, the surface winds are weak and less able to transport heat away.
“Together with the more intense solar radiation, it helps explain the record temperature earlier in May,” said weather and climate scientist at the Singapore University of Social Sciences Associate Professor Koh Tieh Yong.
Climate change and what’s known as the urban heat island effect have been pushing temperatures up.
“The warmer temperatures we’ve been seeing are expected as climate change generally increases global temperatures over the past 40 years,” said climate scientist at the Singapore Management University Associate Professor Winston Chow.
He added that there is a strong urban heat island effect from Singapore’s built-up areas, which stores heat during the day and releases it at night.
Despite the sweltering heat, the temperatures are not high enough within a day and don’t persist long enough between days to cross the thresholds necessary to be declared a heatwave by Met Service, said Assoc Professor Koh.
“The risk will be higher if there’s no rain forecast during this period,” added Associate Professor Chow.
“But it appears that there will be showers in the pipeline to lower the average temperatures and cool us from the heat.”
Based on past records, Singapore experiences on average one to two heatwaves per decade, said the Met Service. The last one was in 2016.
Nevertheless, there has been a “strong and significant” trend of rising temperatures in Singapore, especially since the 1970s, noted Associate Professor Chow, pointing to figures by the Met Service.