Risk of Heat Wave Events in Singapore and Development of Advance Warning Systems for Weather-dependent Sectors

The Senior Minister of State for Sustainability and the Environment (Dr Janil Puthucheary) (for the Minister for Sustainability and the Environment): Mr Speaker, Sir, in Singapore, a heat wave is declared when the daily maximum temperature averaged across all weather stations is at least 35oC for three consecutive days and the average daily mean temperature throughout the period is at least 29oC. Based on the weather outlook, the chance of a heat wave occurring in Singapore during the remainder of the 2026 hot season, which ends in May, is low.

The Meteorological Service Singapore (MSS) issues fortnightly outlooks and four-day forecasts of weather conditions, including high temperatures. MSS also closely monitors climate phenomena, such as El Niño, and works with the Mercury Taskforce to issue advisories, including to weather-dependent sectors, if it expects extended periods of high temperatures.

The Government has heat stress management initiatives on an ongoing basis regardless of whether a heat wave is forecasted. This includes the Heat Stress Advisory which provides simple tips for the general public to plan prolonged outdoor activities based on prevailing heat stress levels, complemented by sector-specific measures, such as the Ministry of Manpower's (MOM's) heat stress framework for outdoor work.

Thank you, Sir. I thank the Senior Minister of State for his reply. Sir, recent reports indicate that parts of Southeast Asia, including Thailand, have experienced extreme heat conditions, with the heat index level exceeding 50oC, and therefore being classified as posing serious danger to human health.

So, in view of this developments, may I ask the Senior Minister of State: one, given that Singapore's current approach is based on a heat stress advisory, whether the Ministry considers this sufficiently robust and actionable, or if there are plans to introduce a more formalised alert system, with clear thresholds and corresponding response measures? Are there also plans to increase the number of sensors that we put around various parts of Singapore?

My second question relates to Singapore being a highly urbanised city-state. I would like to ask whether the Ministry has assessed how the urban heat island (UHI) effect may amplify heat stress in Singapore and how this risk is currently being factored into our national heat resilience planning?

And lastly, on worker protection, can the Senior Minister of State clarify whether existing heat stress guidelines for employers remain adequate in the event of a more prolonged or intense heat conditions? Because I note that current heat stress measures are focused more on outdoor workers. Will the Government consider extending more formal protections or guidance to other at-risk sectors, such as indoor, non-air-conditioned workplaces, because most of our factories are non-air-conditioned, as well as for delivery riders who spend a lot of time outdoors?

Sir, I thank Mr Melvin Yong for his questions. He first asked about the advisory and whether it needed to be more formal, and whether it was robust and actionable. I would characterise our position thus: and I would say it is robust, it is formalised, it is actionable. Of course, we will continue to improve it. We have had the Mercury Taskforce – it was reported in the news, discussed in this Chamber since 2023 – and this brings together public sector agencies, more than 30, looking at what are the various response plans that are sector-specific, domain-specific and under the regulatory aegis of the various agencies.

The heat advisory that goes out is clearly defined. In my original answer, I explained what a heat wave was. There are clear definitions that we have been using in Singapore since 2016, if I recall. It was then last revised in 2023. And so, it is objective, it is measurable, it is specific. [Please refer to ​"Clarification by Senior Minister of State for Sustainability and the Environment", Official Report, 6 May 2026, Vol 96, Issue 30, Correction By Written Statement section.]

And then, agencies – he cited the example of MOM looking at outdoor workers – have developed action plans. These then are triggered by the information that is provided by the MSS. So, MSS, the National Environmental Agency, has a certain set of definitions. When the thresholds are reached, advisories are issued that fall into certain pre-specified categories. And then, various agencies and regulatory bodies will activate their action plan.

So, the formalised, robust, actionable processes are already there. Of course, as related to his later questions, these can and will be improved. And I will speak about that in a minute.

He asked about the number of sensors. We have relatively good coverage. The Member can file a separate Parliamentary Question (PQ), a written PQ perhaps, about the specific number. From memory, I think we have 19 weather stations. Historically, not all of them were used for heat reporting, but today, all of them are, for air temperature. And then, we have, if I recall, another 27 Wet-Bulb Globe Temperature stations across Singapore. So, our overall coverage for sensors is pretty good.

Again, this issue of the data that we get, as well as the answers to his other two questions – whether we need to study the UHI effect on our action plans and whether we have adequate worker protections against heat stress – these issues are the sorts of things that the Heat Resilience Policy Office that we announced in the Committee of Supply this year will indeed coordinate across the whole-of-Government, to look and to see how we make sure our action plans for heat resilience adapt to the changing environment and to the changing risk environment that the Member described in his supplementary question.

So, the short answer to the second half of his first supplementary question is about the sense-making, as well as his other two questions – this is work that the Heat Resilience Policy Office will indeed be taking up.