We demonstrate that heat inhibits learning and that school air-conditioning mitigates this effect. Student fixed effects models using 10 million PSAT-retakers show hotter school days in years before the test reduce scores, with extreme heat being particularly damaging. Weekend and summer heat...

We provide the first evidence that cumulative heat exposure inhibits cognitive skill development and that school air conditioning can mitigate this effect. Student fixed effects models using 10 million PSAT-takers show that hotter school days in the year prior to the test reduce learning, with...