From its distinctive smell to the negative ions it releases, rain has some fascinating benefits for our bodies – especially when it comes to our mood.

It turns out that after decades of studying the elements of rain’s potential mood-boosting abilities, scientists have found some decent evidence to support it. And it’s not the only benefit of rain: research shows rain also removes harmful substances from the air, while its unmistakable smell may even enhance our memories.

The predominant reason may be that rain releases negative air ions – oxygen molecules with an extra electron, which form as raindrops collide or hit a surface and split apart. In high levels, these are known to boost serotonin and alpha waves in the brain, leading to a happier, more relaxed state.

When raindrops hit the ground, they can splatter and release negative ions into the air – a process called the Lenard effect. So if you’re hoping to get a sizeable dose of serotonin-boosting negative ions, try taking a walk in a rainstorm. Just make sure to get inside if you see lightning – for safety’s sake.

Some scientists believe these positive effects may be due to negative air ions increasing oxygen levels in the blood, resulting in a mood boost akin to what you experience from intense exercise. However, there still isn’t conclusive evidence to explain exactly what mechanism is going on to produce these effects. Pam Dalton, a cognitive scientist at the Monell Chemical Senses Center in Pennsylvania in the US, notes it is still not well understood why negative ions have effects such as changes in mood as well as fatigue, cardiovascular status and blood pressure. Rain’s negative ions also appear to clear the air of particulate matter such as pollution and allergens, making it easier to breathe. This could have an impact on mood and health as well: since poor air quality is associated with increased anxiety and risk of developing more severe mental health disorders, it stands to reason that cleaner air would promote the opposite.

Rain’s distinct smell can also have a psychological impact. Known as petrichor, this odour rises out of the ground after a storm and is often described as pungent and earthy, yet somehow clean.

It’s not just smelling and breathing in rain that can make us feel good, though; it’s hearing it too, which is why you often find rain tracks on sound machines. A steady rain can reduce cortisol levels, inducing a sense of calm, as well as drowning out disruptive noises.