In the 1990s, researchers proposed the ‘heat hypothesis’ to explain the fact that violent crimes go up in the summer (the US murder rate, for example, rises by about 2.7 per cent), and that aggressive acts are often more common in hotter countries – the basic idea being that warmer temperatures make us more prone to losing our temper and lashing out.
Of course, there are many alternative explanations for these heat-crime links, such as more people being out and about in hot weather (thus increasing the risk of random altercations). But multiple studies have confirmed that you’re not alone in finding that hot weather makes you liable to tantrums. In 2016, for example, psychologists at Texas Tech University found that American football players were more likely to commit aggressive fouls during hotter weather.
The main psychological explanation is that because heat makes us feel physically uncomfortable, we’re more inclined to aggressive thoughts and to interpret things in a negative way.
There are tentative biological explanations, too, with recent Scandinavian research identifying a link between higher temperatures and raised serotonin levels – a brain chemical that’s related to impulsivity, among other things.
So just like Bruce Banner, it’s probably worth making the extra effort to keep cool in hot weather, both literally and emotionally.