There’s a Scientific Reason Why Summer Heat Makes Us So Grumpy

Updated: Jun. 30, 2017

...and it has nothing to do with the kids being home from school.

Do the 90-degree-plus temperatures have you feeling a bit crabby? If you’ve snapped at your kids or spouse (or maybe even a stranger) lately, you can officially blame the weather—and it’s totally scientifically accurate.

According to research published in the European Journal of Social Psychology, three separate studies have all yielded the same conclusion: The summer heat isn’t just getting on our nerves. It makes everything else get on our nerves, too! (Want to beat the heat? Try these tricks to stay cool this summer.)


First, researchers surveyed data from a 2010 study conducted in Russian shopping malls during a summer heat wave. Because none of the stores had air conditioning, the scientists wanted to see if the heat would affect the employees.

Sure enough, “store employees really seemed to be feeling the heat,” Mental Floss reported. Employees were 59 percent less likely that summer to engage with shoppers by offering their assistance or making suggestions. In other words, although the stores were spotless, the human relations aspect of the job was significantly lacking.


For the second experiment, researchers asked 160 participants to take an online trivia quiz. While half of the participants were instructed to imagine themselves in an uncomfortably warm setting before starting the quiz, the “control” group took it without instructions. After the quiz, they were all given an optional survey about their experience. Those who thought about being hot were over 30 percent less likely than everyone else to agree to do it. They also reported feeling more tired and less happy than the other participants.

The final study placed college students in the same class on organizational management, but in two sessions—once in a stuffy room (80°F) and once in air conditioning. 35 students in the air-conditioned room answered the optional survey questions. As for those in the hot room? Only 6!

“The point of our study is that ambient temperature affects individual states that shape emotional and behavioral reactions,” said Liuba Y. Belkin, lead researcher, “so people help less in an uncomfortable environment, whatever the reason they come up with to justify why they cannot do” certain things.

There you have it! All the more reason to invest in air conditioning—no matter where you live. But our mood isn’t the only thing that the heat affects. Summer can also trigger diabetes problems—and here’s how.