The American Psychological Association and the Network for Resilient PK-12 Schools released their first joint report on extreme heat in schools in August 2026, calling on districts to treat high temperatures as a disruption to cognition equivalent to a snow day. The report, "Schools, Climate, and Health: Responding to Extreme Heat," synthesizes peer-reviewed studies that document how rising classroom temperatures affect students' attention, memory, test scores, and mental health.
The report recommends that schools postpone high-stakes exams on hot days, adjust daily schedules, and establish formal heat thresholds with monitoring and accountability structures. It identifies an optimal classroom temperature range of 68 to 73 degrees Fahrenheit, and finds that above 73 degrees, students complete cognitive tasks more slowly and less accurately, with effects worsening as temperatures rise.
What the research shows
The evidence base the report draws on includes several large-scale studies. R. Jisung Park's 2022 study in the Journal of Human Resources analyzed 4.5 million New York City Regents exam records and found that taking an exam on a 90-degree day versus a 72-degree day reduced performance by 0.15 standard deviations and increased the likelihood of failing a subject exam by 12.3 percent. The study also linked hot exam days to a 2.5 percentage point reduction in on-time high school graduation.
Park's earlier 2020 study in the American Economic Journal: Economic Policy used data on 10 million PSAT retakers and found that each additional degree Fahrenheit above the average school year temperature reduced learning by about 1 percent in schools without air conditioning. That study attributed roughly 5 percent of the racial achievement gap to heat exposure, with minority students disproportionately affected.
For younger children, research by Jorge Cuartas published in 2025 in the Journal of Child Psychology and Psychiatry examined 19,607 children aged 3 to 4 across six countries. The study found that children exposed to average maximum temperatures above 32 degrees Celsius (89.6 degrees Fahrenheit) were 1.8 to 7.7 percentage points less likely to be developmentally on track, with the largest effects in literacy and numeracy. The impact was most severe for children in economically disadvantaged households and urban areas without adequate water and sanitation. The study's authors note that its cross-sectional design and reliance on parent-reported measures limit causal certainty.
Comparative evidence on cooling and adaptation
The report's supporting research also provides evidence on interventions. Park's 2020 study found that school air conditioning can offset the majority of heat's effect on learning: in fully air-conditioned schools, hot school days reduced learning by only one-fifth as much as in schools without cooling. The study estimated the present value of air conditioning for a 1,000-student high school in a hot area such as Houston, Texas, at roughly $2.1 million per year, based on projected achievement-to-earnings relationships.
Park's New York City Regents exam study documented an earlier form of adaptation that has since been removed: before the city eliminated teacher grading discretion in 2011, teachers appear to have boosted grades around passing thresholds during hot exam sittings. The study found roughly 1.5 percent more grade manipulation per degree Fahrenheit, an adjustment the authors say may have partly protected low-achieving Black and Hispanic students from heat-related academic harm.
Implications for district readiness
The report notes that extreme heat disproportionately affects younger children, low-income families, and schools in older buildings that lack adequate cooling systems. Rocky Mountain and Southwest states — Wyoming, Idaho, Utah, and Colorado — have experienced the largest percentage increases in heat days among Mountain West states, according to data from the nonprofit Center for Climate Integrity cited in the report's coverage. The report urges districts to designate heat leadership, develop threshold-based policies for indoor and outdoor activities, and ensure automatic protections for vulnerable students.
The report is the first from the Network for Resilient PK-12 Schools. A forthcoming systematic review by Cuartas and colleagues, expected in the journal Clinical Child and Family Psychology Review in 2026, aims to consolidate the broader evidence on prenatal and early childhood heat exposure, an area the authors describe as still emerging.