Rainfall affects our mood, our propensity to commit crime and how hungry we feel – but why?
It’s raining, it’s pouring, the old man is snoring. He bumped his head when he went to bed, and he couldn’t get up in the morning. This was possibly because in the absence of sunlight his body was still producing the hormone melatonin, which makes you sleepy. There are many ways that rainfall affects human behaviour. Why do crime levels drop when the heavens open? How much does rain really affect people’s moods and behaviour?
In 2008 university researchers published a paper proposing that weak summer monsoons were influential in the downfall of three dynasties in ancient China. By analysing stalagmites from a cave, they were able to match periods of significantly decreased rainfall with periods of social upheaval and the demise of the Tang, Yuan and Ming dynasties. This is thought to be related to reduced rice cultivation.