In years with hotter weather pupils are likely to perform less well in exams, says a major study from researchers at Harvard and other US universities.

哈佛等美国大学的研究人员开展的大型研究指出，在天气炎热的年份，学生们的考试成绩会变差。

There is a" significant" link between higher temperatures and lower school achievement, say economic researchers.

An analysis of test scores of 10 million US secondary school students over 13 years shows hot weather has a negative impact on results.

The study says a practical response could be to use more air conditioning.

Students taking exams in a summer heatwave might have always complained that they were hampered 1 by the sweltering weather.

But this study, from academics at Harvard, the University of California Los Angeles (UCLA) and Georgia State University, claims to have produced the first clear evidence showing that when temperatures go up, school performance goes down.

Researchers have tracked how secondary school students performed in tests in different years, between 2001 and 2014, across the different climates and weather patterns within the US.

The study, published by the US National Bureau of Economic Research, found that students were more likely to have lower scores in years with higher temperatures and better results in cooler years

This applied 2 across the many different types of climate - whether in cooler northern US states or in the southern states where temperatures are typically much higher.

The study, Heat and Learning, suggested that hotter weather made it harder to study in lessons in school and to concentrate on homework out of school.