I have always been obsessed with the weather, and the weather has always affected me deeply. My earliest memories combine weather and powerful emotions: the fear I experienced when caught in a thunderstorm in London with my father, the joy of playing in snow with my relatives during the great winter of 1962–63, the awe of seeing a magnificent double rainbow from our garden, and the wonder of watching a cumulus cloud evolve on the way home from school. That sense of wonder helped lead me to science.

Does the weather shape the way we think?

It took me decades as an academic psychologist to realise that I could combine my two great passions, psychology and meteorology, by looking at how weather affects our minds. There is a surprising amount of research on this subject, but the field is still young and much remains unknown. One complication is that, just as we differ in personality dimensions such as extraversion or neuroticism, we may also differ in our “weather personalities”. For example, contrary to common assumption, not everyone likes it warm and sunny. For a minority, long bright days may even be associated with low mood.

The best-known way in which weather affects mental health is Seasonal Affective Disorder (SAD), in which lack of winter light affects mood, ranging from “winter blues” to severe depression. In some people the lack of light affects their biological clock, which in turn affects their mental health. I suffered from SAD for many years without realising it — an ironic lack of insight for a psychologist. I now manage it with a morning lightbox in winter, vitamin D supplementation, and a dog who ensures I go out every morning, whatever the weather. Anyone with persistent or serious depression should seek medical advice.

Does the weather affect how we interact with each other?

Some social psychology experiments suggest a basis for calling someone “cold-hearted”: physical warmth and coldness may subtly influence social judgement and generosity. These findings, however, have not always replicated, so they should be treated cautiously. Weather can also affect our decisions. One study found that students visiting a university on sunny days paid more attention to social and sports facilities, while those visiting on cloudy days focused more on academic reputation. Another study found that interviewers of potential students gave more weight to academic qualities on cloudy days and more to extra-curricular factors on sunny days.

The downside of heat

Heat does not cause violence on its own, but it can add pressure to already tense situations. Summer also brings more people outdoors, often drinking alcohol, so the causes are complicated. Even so, there is evidence that high temperature can increase hostility and aggression, and violent crime tends to rise as the weather heats up. It is said that police sometimes long for cold, wet weather after a heatwave.

The upside of rain

Rain is often associated with lower mood, perhaps partly because rainy days are also often darker. Sunshine improves mood for many people and may enhance creativity. Yet rain has its own benefits. People may focus better on routine or demanding tasks when it rains. Rain can also clear allergens from the air, and some research has explored whether negative air ions affect mood and fatigue, although the evidence remains mixed. Rain releases geosmin from the soil, a component of petrichor, “the smell of rain”, which may itself have mood-enhancing effects.

Few like the wind

Although we differ in what weather we prefer, I have found that relatively few people like windy weather. Wind can increase anxiety, partly because people fear disruption, and perhaps because it affects allergens and other particles in the atmosphere. Some named winds, such as the Khamsin and Föhn, are notorious for their effects. Joan Didion’s famous 1967 essay “The Santa Ana” describes the unease that wind brings to California.

The weather brings out the best in us

There is now a large body of research showing that exposure to nature can benefit mental health. Weather is part of nature: the awe induced by a rainbow or thunderstorm, the calm of rain, or the feel of a breeze on your skin on a hot day.

The useful question is not simply whether weather affects people, but how it affects you. Do you sleep worse in heat? Feel trapped by grey days? Work better when it’s raining? Feel energised by cold air? Keeping a simple note of mood, sleep, light, and weather can help you recognise patterns.

So look at the skies, notice what changes in you, and find your own ways to experience the weather.