This paper uses data from 2003–19 on 2.47 million test takers of a national high stakes university entrance exam in Ethiopia to study the impacts of temperature on learning outcomes. It finds that high temperatures during the school year leading up to the exam reduce test scores, controlling for temperatures when the exam is taken. The results suggest that the scores of female students are less impacted by higher temperatures compared to their male counterparts. Additionally, the analysis finds that the scores of students from schools located in hotter regions are less impacted by higher temperatures compared to their counterparts from cooler regions. The evidence suggests that the adverse effects of temperature are driven by impacts from within-classroom temperatures, rather than from indirect impacts on agriculture.