With temperatures soaring amid Singapore's hottest months of May and June, 43-year-old Clement Tan is concerned about how the heat is affecting his children in school.

“Their school is in an older building and I’ve been there for meet-the-parents sessions. The fans do not provide ventilation throughout the whole classroom and it can be really uncomfortable at certain parts of the classroom,” said Mr Tan, a litigation lawyer and father of three children aged 10, seven and five.

He has equipped his two older children, who study at Fairfield Methodist School (Primary), with handheld fans to give them some reprieve from the weather. The school has also allowed students to wear their Physical Education (PE) uniform throughout the day, which has helped keep them cool and complaint-free.

But as his children have eczema – a condition that causes skin to become dry, itchy and bumpy and is exacerbated by heat – rising temperatures have caused flare-ups.

Several parents told CNA TODAY they were worried about how the stifling heat in school, during the commute as well as at home is affecting their children’s learning abilities.

These parents' fears are not unfounded: Extreme heat conditions can impact students, with several studies pointing out lower grades and inability to focus as temperature rises, some education and environmental experts said.

Singapore has experienced six historical heatwave events, with the most recent one in 2016. Heatwaves are when the highest daily temperature is at least 35°C for three consecutive days and the average temperature every day is at least 29°C.

In May 2023, the highest daily maximum temperature of 37°C was recorded, tying with that recorded in 1983.

May has always been one of Singapore's hottest months. This year, from May 23 to May 28, the highest daily temperatures ranged between 35°C and 36.2°C around the island.

With the effects of climate change, including rising average temperatures and heavier rainfall, experts predict that more students will likely fall ill and miss school.

While calling for more air-conditioned classrooms may seem like the most obvious recourse, they added that doing so too often could impact children's heat tolerance and ability to handle rising temperatures in the longer term.

In preparation for future rising temperatures, the Mercury Taskforce led by the Ministry of Sustainability and the Environment, and the National Environment Agency was set up in 2023 to create a national heatwave response plan.

Should a heatwave occur, students will be allowed to wear dress-down attire such as dry-fit material uniforms. Outdoor activities will also be minimised between 11am and 4pm, or suspended if heat stress levels spike, the taskforce recommended.

And should there be a need for heightened measures, schools may switch to either partial or full home-based learning.

The Ministry of Education (MOE) said that it refers to both local and international studies related to thermal comfort and that schools have both guidelines from the ministry as well as the autonomy to determine measures to help students manage the heat.

Besides adopting the heatwave response plan by the taskforce, which the ministry is a part of, MOE has also taken measures to improve the ventilation of classrooms.

“New schools are also designed to facilitate natural cross ventilation through the use of computer simulations on air flow and wind velocity," said MOE.

“MOE is also progressively adopting additional measures to enhance thermal comfort in classrooms, such as adding more fans and changing them to energy-efficient direct current models, and painting school building exteriors with cool paint."

STUDENTS ARE GRUMPIER, CRANKIER, MORE IRRITABLE

Despite these moves, Ms Rynette Joyce Tan’s children have been “more cranky than usual” with the highest daily temperatures of 36.2°C in the latter half of May.

"They complain as they get itchy and irritable from being too warm. They (also) get agitated more easily, tend not to speak too nicely to each other and get set off more easily," she said.

The founder of childbirth education platform 13Thirteen is the mother to four children, aged 11, 10, seven and five.

“Our kids usually take the public bus to school on their own, but lately they’ve been asking us to pick them up more often,” she said.

“Sometimes they’ll even catch a ride with a friend’s parent if they can. I think they’re drained from the heat by the end of the school day.”

Her children's school also switched the material used for its school uniform to a lighter, moisture-wicking fabric. This has helped make the heat more bearable, said Ms Tan.

At home, the family has adopted additional measures to keep the children cool.

“We don’t usually use the air conditioner during the day, but with this heat, we’ve told the kids it’s okay to switch it on, especially when they’re studying for exams and need to concentrate,” she added.

While Singapore has not halted schools due to heatwaves and rising temperatures, a United Nations Children's Fund (UNICEF) analysis released in January 2025 found that one in seven students had their school disrupted due to climate hazards last year.

Heatwaves were the most significant climate hazard to disrupt schooling, affecting roughly 171 million students in 2024, the UNICEF analysis found.

The month of April had the highest global climate-related school disruptions as heatwaves affected 118 million children in South Asia and Southeast Asia.

Some schools were shuttered entirely for several days, such as in the Philippines, when temperatures soared over 40°C. They were also closed in the later part of the year as typhoon season flooded classrooms, or schools were used as temporary evacuation centres.

Over in Cambodia, schools tried to help students escape the sweltering heat by shortening the school day by two hours.

In Latin America, meanwhile, 48 million children face double the number of 35°C or higher days than 60 years ago, said UNICEF in its analysis.

The United States is also not free from the effects of rising temperatures. Last year, several schools closed their doors as inadequate air-conditioning systems failed to keep classrooms cool, reported British news outlet BBC.

Assistant Prof Wang Jingyu from the National Institution of Education at Nanyang Technological University said that Singapore’s students face milder climate impact compared with developing neighbours in Southeast Asia as the island has advanced infrastructure and policies.

However, Singapore faces similar challenges experienced by developed countries like the United States and Australia.

"Despite differing climates, developed countries often face similar pressures in adapting their urban systems and educational environments to increasing climate variability and extremes," said Ast Prof Wang.

Similar challenges include urban heat stress, exposure to extreme weather events, air quality issues, and the need for resilient infrastructure so that classes can continue uninterrupted.

Former teachers also told CNA TODAY that they notice students are more distracted when it is hot. Mr Erika Kua, a former H2 chemistry teacher, said that it was exceptionally bad while doing science experiments involving heating, as the fans in the laboratory had to be switched off.

The founder of tuition centre Mr Khemistry had taught at Meridian Junior College from 2006 to 2011, as well as from 2014 to 2017. The school is now known as Tampines Meridian Junior College.

Students would be talking among themselves, fanning themselves with worksheets, moving around in their seats or wiping their arms and necks, he said.

“It's hard to expect them to focus deeply when they're uncomfortable. The heat really does make it hard to think clearly,” said Mr Kua.

Mr Tan, the litigation lawyer and father of three, added that his two older children also play tennis competitively.

“I have to thank the coach and teachers for always reminding them to hydrate and reapply their sunblock to protect themselves,” he added.

He encourages his children to take a cool shower once they are at home, as well as to drink plenty of water and sit under a fan. The air conditioner is only turned on when the humidity and heat are “too stifling”.

To beat the heat, the family also regularly consumes barley water, which Mr Tan’s in-laws diligently make every weekend to ensure the children are hydrated.

As for 52-year-old Edwin Lee, he is more concerned about the long-term impact of the fluctuating extremes in weather. The service controller is the father of an 18-year-old son and 14-year-old daughter.

Unlike the parents of younger children in primary school, he said his children are “old enough to know how to care for themselves” when it gets too hot.

“With the weather getting increasingly unpredictable, one moment (there is) a heatwave, the next, a sudden downpour and flooding. I do think schools might want to start thinking ahead,” he said.

HOTTER DAYS AFFECT ACADEMIC OUTCOMES

Several studies have found that heat impacts education outcomes and cognitive abilities.

Associate Professor and Dean’s Chair of the National University of Singapore’s (NUS) Department of Economics Alberto Salvo is part of a team of academics studying how heat has impacted college students in Singapore.

Looking at undergraduate course records between 2005 and 2019 at one of Singapore’s universities, his team's paper – titled "Heat impacts college student grades even in rich Singapore" – revealed that students' performance reduced by 1.5 per cent when semesters were hotter than usual.

Assoc Prof Salvo said the study did not find any "robust" evidence that students from low-income backgrounds, such as those living in rental flats, were more sensitive to the heat. However, this could be because such students find ways to mitigate the heat, such as going to libraries or malls with air-conditioning.

While his study focused on university-going students, he told CNA TODAY that it could be worthwhile for MOE to see if this trend stands among younger students.

Agreeing, Assistant Prof Wang Jingyu from the National Institution of Education at Nanyang Technological University said that several studies have shown that students' cognitive performance scores decreased significantly with increased temperature and decreased air velocity.

“Prolonged heat exposure in non-air-conditioned classrooms may increase fatigue and decrease participation,” she added.

But are children so susceptible to the heat?

To this, experts from the Heat Resilience and Performance Centre at NUS's Yong Loo Lin School of Medicine said that children may be less aware of their own thermal discomfort and less likely to communicate symptoms of dehydration or overheating.

This could put them at higher risk during both indoor and outdoor activities, said Assoc Prof Jason Lee and Ms Lydia Law, the centre’s director and co-director respectively, in a joint response.

Warmer nights might also lead to disruptions in sleep, reducing attention span and focus.

Nevertheless, children have physiological characteristics which help with heat loss under moderate conditions, said the experts. This includes having “greater surface area-to-body-mass ratio and higher skin blood flow”.

“They also generally have lower sweat rates than adults, although this may not be a disadvantage in our high humidity environment,” said Assoc Prof Lee and Ms Law.

Dr Ho Boon Tiong, principal consultant educationist at training and consulting firm ClassPoint Consulting, added that some children might be more sensitive to the heat, such as those with skin conditions like eczema.

He added that the heat could widen inequality among some students. For example, students who do not have air-conditioning at home may not be able to study well at home when it's hot unlike their peers who have access to cooler rooms.

“It’s a known fact that better resources will lead to better outcomes, and learning environments are affected by the temperature,” he said.

This also applies to schools that may be better-resourced, such as those that have air-conditioned classrooms.

Teachers will also face increased physical strain and diminished teaching effectiveness in a warming climate, added Asst Prof Wang.

“In non-air-conditioned classrooms, high temperatures sap energy and focus, compromising lesson delivery, while frequent shifts between home-based and in-person learning demand extra preparation time,” she said.

“Beyond logistical burdens, teachers also bear the emotional toll of supporting vulnerable students – particularly those without adequate cooling or study spaces at home – further compounding stress and burnout risks.”

Professor of Urban Climate at Singapore Management University Dr Winston Chow warned that extreme weather and heat can also lead to negative after-effects.

This includes a rise in vector-borne diseases like dengue, as Singapore’s hot and wet climate accelerates the physical maturation of the mosquitoes, which could increase school absenteeism.

He added that mental health conditions could be worsened by the heat. There could be more climate anxiety, which is a sense of panic, worry and fear towards the consequences and uncertainty brought by climate change, said Dr Chow.

WHAT CAN BE DONE?

Responding to CNA TODAY's queries, MOE said it "recognises the importance of providing conducive learning and examination environments for our students in schools, while striving for our schools to be environmentally sustainable in their operations".

It added that standard classrooms are designed to be naturally ventilated without using air-conditioning, such as placing classrooms in the North-South orientation to minimise heat gain, and optimising natural cross ventilation through sunshades, fans and ample window openings.

In more severe heat situations, MOE, with reference to national advisories, may suspend outdoor activities or all physical activities. Where necessary, the ministry will also provide schools with more guidance.

But is the solution simply installing air conditioners in classrooms? The short answer is no.

“Air conditioners offer short-term relief but come with long-term trade-offs. Cooling accounts for roughly 30 per cent of Singapore’s electricity consumption, with related emissions projected to rise by 39 per cent by 2030 without clean cooling measures,” said climate and sustainability director and global palm oil lead at the World Wide Fund for Nature Singapore (WWF-Singapore) Kamal Seth.

“Relying solely on air conditioners would create a vicious cycle, intensifying the very heat crisis we’re trying to escape."

Ms Law and Assoc Prof Lee of the Heat Resilience and Performance Centre said that children may become less heat resilient due to excessive time spent indoors.

"Individual resilience can be promoted by encouraging students to progressively and safely acclimatise to warm environments instead of avoiding outdoor activity altogether,” they said.

They added that regular physical activity and gradual exposure can enhance the body’s ability to cope with heat stress.

To enhance the effectiveness of existing measures, like allowing students to wear cooler clothes, Dr Chow suggested that weather predictions should be made more accessible to the schools.

This will allow school leaders to anticipate and better handle extreme weather conditions ahead of time, he said.

Teachers also play a role in ensuring students are not too affected by the heat by reminding students to hydrate and observe for signs of heat stress.

Asst Prof Wang added that teachers should be equipped with “climate-adaptive instruction” by modifying curriculum or classroom management in response to weather and climate-related disruptions like extreme heat, haze or urban floods.

She said, for example, outdoor physical activities can be replaced with heat-resilient alternatives like swimming or indoor spots.

“Parents and communities play a key role by preparing cool, quiet study spaces at home, educating children on safety practices, and partnering with schools to identify and support at-risk students,” she added.

Asst Prof Wang said that while switching to home-based learning and limiting PE classes may be necessary in extreme heat conditions, such adaption measures may present “nuanced education trade-offs.

“While these measures mitigate heat stress and maintain academic continuity during extreme weather, reduced outdoor activities may impact physical development and social interaction,” she said.

“Home-based learning effectiveness hinges on equitable access to technology and home cooling, potentially exacerbating learning disparities.”

On this note of thermal inequality, a spokesperson from SG Climate Rally said that air-conditioned cooling centres should be provided with space for students to attend their classes and do their homework such as in libraries or community centres.

“While ensuring equitable access to air-conditioning during high heat events is a must, we also need to prevent overuse of it when not necessary, such as setting the thermostat higher and switching to more efficient models,” added the spokesperson.

In response to CNA TODAY's question about closing schools in the event of extreme heat conditions, MOE said that "any decision to close schools will not be taken lightly as we are mindful of the disruptions to families' care arrangements for their child".

“In the event a school closure is necessary due to a severe hot weather situation, MOE may implement partial or full Home-Based Learning in schools to safeguard the safety and well-being of all staff and students while ensuring the continuity of teaching and learning," said MOE.

“Schools and school-based Student Care Centres will continue to support parents who may require alternative arrangements.”

RETHINKING SCHOOL INFRASTRUCTURE

What about infrastructure changes? Ms Elaine Tan, the Singapore sustainability leader at global sustainable development consultancy Arup, said some design choices can make newly-built schools cooler.

“Where and how the building sits on the site plays a huge role. For instance, minimising east- and west-facing facades helps reduce exposure to intense morning and afternoon sun, while aligning buildings with prevailing wind directions makes the most of natural ventilation,” she said.

“The choice of window systems, such as jalousie, side-hung, or sliding windows, and its location and height, significantly influence wind movement and indoor comfort,” she said.

Jalousie windows have multiple horizontal slats or panes of glass that can be tilted open and closed together to control airflow, and is a common feature in Singapore's schools.

All the experts also agreed that more education around climate change and sustainability among children is needed to help combat the root cause of our rising temperatures.

NTU’s School of Mechanical and Aerospace Engineering Assoc Prof Wan Man Pun added that the school’s surroundings matter too.

“When building a new school that will be naturally ventilated, selecting a location that is less subject to wind blockage by surrounding structures or away from highly dense built-up areas will be of great help,” he said.

He added that designing external architectural elements such as low emissivity glass for windows – a type of glass with a thin, transparent, microscopic coating that reflects heat – can manage heat gain in the building structure.

“These are some passive, non-energy-consuming measures (that) could be taken before involving active energy-consuming measures such as air-conditioning and mechanical ventilation,” he said.

But what about existing schools, whose buildings may be older? Ms Elaine Tan said incorporating green spaces such as green planters, roofs and walls can absorb heat. Installing “blue infrastructure”, such as water features, can also help cool surrounding areas.

A study conducted by Arup found that there can be a 6.5°C difference between the most intense hot spot and the coolest spot near areas with greenery and water bodies.

However, she added that it is also important to ensure these new facilities can be easily maintained, among other things.

Assoc Prof Wan added that classrooms could reduce the density of heat by limiting the number of students and equipment that might emit heat in classrooms.

While parents who spoke to CNA TODAY immediately suggested that air-conditioning is the only solution should temperatures continue to rise and heatwaves become more frequent, they acknowledged that schools are already doing a lot to help students cope, and there's not much else that can be done.

Still, some parents had creative ideas to offer.

One parent suggested making uniforms more weather-resistant, and another said that misting fans could be installed in schools to help children cool down.

“Even something more adaptive, like zip-off pants that convert to shorts when it’s hot, or can be removed quickly if they get wet during heavy rain or flood, could be useful," suggested Mr Edwin Lee, the parent of two.

Handheld fans, sunblock routines, breathable uniforms: How Singapore students and schools are beating the heat and staying cool