Too Hot to Learn: Rising Temperatures Threaten Exam Scores and Education Equality in Cambodia

An Asian Development Bank study of over 730,000 Cambodian students reveals that prolonged extreme heat reduces learning outcomes, increases examination failure risks, and disproportionately affects girls, rural students, and disadvantaged communities. The findings urge governments to invest in climate-resilient schools, better cooling facilities, flexible academic schedules, and targeted support to protect education and future economic opportunities.

Rising temperatures are becoming a serious threat to education, with new research showing that prolonged exposure to extreme heat can reduce students' learning abilities, weaken examination performance, and deepen educational inequalities. A study published by the Asian Development Bank (ADB) in October 2026, conducted by researchers from the Paris School of Economics, the University of California, Berkeley, and the Asian Development Bank, reveals that students from disadvantaged backgrounds face greater risks. Titled Effects of Extreme Temperature Exposure on Learning, the research examines examination records from 731,279 Cambodian students between 2014 and 2023, highlighting how climate change could affect education, workforce development, and future economic growth.

The researchers combined Grade 12 national examination results with detailed climate records to understand how sustained heat exposure affects learning throughout the academic year. Cambodia provides an important example because of its tropical climate, high humidity, and limited cooling facilities in many schools. The country has experienced average temperature increases of approximately 0.18 degrees Celsius per decade since the 1960s, raising concerns about the long-term consequences for students.

Rising Heat Is Quietly Damaging Classroom Learning

The study found that a one-degree Celsius increase in the average school-year heat index was associated with a decline of approximately 0.046 standard deviations in examination scores among social science students. The heat index combines temperature and humidity to measure how hot conditions feel to the human body.

During the study period, the average school-day heat index was 30.48 degrees Celsius, while students experienced approximately 76 school days annually when the index exceeded 31 degrees Celsius. Ten additional days with heat index readings between 32 and 33 degrees Celsius were associated with a decline of approximately 0.03 standard deviations in social science examination performance.

Researchers explain that prolonged heat exposure can reduce concentration, memory, and problem-solving abilities while increasing fatigue and disrupting sleep. These effects can accumulate over several months, making it harder for students to understand lessons, retain information, and prepare for examinations.

Interestingly, science students showed no statistically significant overall decline in examination performance. Researchers suggest that stronger academic preparation, competitive examination requirements, and greater access to tutoring may help some students cope with difficult learning conditions, although these explanations remain unconfirmed.

Girls and Rural Students Face Greater Educational Risks

The research highlights significant differences in how rising temperatures affect students. Although female students consistently performed better than males in Cambodia's national examinations, girls studying social sciences experienced greater heat-related learning losses.

A one-degree increase in the average heat index was associated with a decline of approximately 0.065 standard deviations in examination scores among female social science students. Researchers suggest that household responsibilities, socioeconomic disadvantages, and limited resources for adapting to heat may contribute to this vulnerability.

Geographical differences were equally important. Students attending schools in relatively cooler regions experienced stronger negative effects when temperatures increased, while those living in consistently hotter areas appeared better adapted.

Rural social science students also experienced significant learning losses during particularly hot school days. Poor ventilation, unreliable electricity, inadequate drinking water, and weaker infrastructure may increase their exposure.

The study found that approximately 32% of schools in its infrastructure data lacked access to water, while reported Grade 12 classroom sizes averaged around 45 students. Such conditions can make learning increasingly difficult during extreme temperatures.

Extreme Temperatures Threaten Examination Success and Future Careers

The consequences of rising temperatures extend beyond everyday classroom difficulties. The study found that geography, history, Khmer language, and mathematics were particularly affected among social science students.

Higher-achieving social science students also experienced significant performance declines, raising concerns about their ability to secure scholarships, enter universities, and pursue competitive careers.

Extreme heat increased examination failure risks. Ten additional school days with heat index readings between 34 and 35 degrees Celsius were associated with a 1.7-percentage-point increase in the probability of failing among social science students.

These findings carry wider economic implications. Poor examination performance can limit access to higher education, reduce employment opportunities, and weaken the development of skilled workers.

Students from low-income households may face additional disadvantages because they often lack cooling equipment, private tutoring, and comfortable places to study. Without protective measures, climate change could widen existing gaps between wealthy and disadvantaged students.

Climate-Resilient Schools Could Protect the Next Generation

The researchers recommend making climate adaptation an essential part of education planning. Governments can improve classroom ventilation, install reflective roofs, expand shaded areas, ensure drinking water access, and reduce overcrowding.

Schools could also adjust academic calendars to avoid the hottest periods and schedule demanding lessons during cooler morning hours. Heat early-warning systems could help authorities introduce protective measures when temperatures become dangerous.

Teacher training, community cooling spaces, and additional academic support for vulnerable students could further reduce learning disruptions.

The report emphasizes that improving school infrastructure alone may not be enough. Students also need protection from extreme temperatures at home, where uncomfortable conditions can interfere with homework, examination preparation, and sleep.

Rising temperatures represent a growing challenge for education systems and long-term economic development. For Cambodia and other climate-vulnerable countries, investing in heat-resilient schools is increasingly important to protect learning opportunities, reduce inequality, and safeguard the skills of future generations.