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After John Constable’s beloved wife Maria died in 1828, the style of his landscapes changed. Gone were the fair-weather clouds and sunny, bucolic mood of the Hay Wain, painted in 1821; the weather depicted after her death becomes dark, gloomy, angry even, with towering, threatening clouds dominating the skies. Look at his paintings of Hampstead Heath and how the clouds and light changes across the 1820s. It is though the gloom in the outside world reflects his inner world of anguish and grief.

Young amateur meteorologist Luke Howard’s book (1818-20) was likely what spurred Constable’s intensive study of the sky and his remarkable cloud studies. Howard’s pioneer cloud classification system also earned the admiration of the German philosopher and writer Johann Wolfgang von Goethe and forever changed our relationship with weather.

Weather and mood seem inextricably linked. We even talk about our feelings in terms we use for the weather (“gloomy”, “sunny disposition”, “a cold person”, and “hot-blooded”), but does it work the other way round? Can the weather affect our mood and how we behave?

Bring me sunshine

At this time of year, in mid-January, where I live in the Sidlaw Hills north of Dundee, the sun creeps over the hill after 9.30 in the morning. It disappears behind another hill at 2.45 in the afternoon.

Winter gets to me as it does to many people, and the lack of sunshine is the most important factor. Too much sunshine can be dangerous: everyone is now surely aware of the link between sunshine and skin problems from ageing to skin cancer, but sunburn in the British winter is unlikely. A far more likely problem is that people have too little sunshine in winter, which has several negative effects. It affects our immune system, cardiovascular health, and mood. In about 10% of the population the lack of light produces a significant deterioration in mood, called Seasonal Affective Disorder (SAD).

We are not helpless against SAD, although severe cases may require medical intervention. We need to get as much natural light as possible, and to get it as early as possible in the day. If you can’t get outside, get a lightbox that simulates sunshine with a very bright blue-white light. I have a daily morning walk and use my lightbox as much as possible in the morning. Light at the right time (morning) is essential for the production of a hormone called melatonin, which is important for regulating the sleep-wake cycle. You might also consider a Vitamin D supplement because sunshine acting on the skin is the main way in which we obtain the vitamin; you don’t need much.

The fascination with the weather impact on human health is not new. Since the second half of the nineteenth century, when the first daily weather forecasts appeared in the Times, advances in both medicine and meteorology have helped us to learn more about the relationship between health and the capricious British weather.

It isn’t just in winter that sunshine affects mood. At any time of year many people feel happier when the sun is shining. Good weather can affect some people in surprising and subtle ways.

Business executives are merely likely to be upbeat about financial forecasts during sunny weather. Sunshine is positively associated with daily stock market returns. A finding in the other direction is that university applicants to competitive institutions are more likely to choose that institution if they visit on a cloudy day: sunshine is seen as a distraction and a disincentive to study. Fine weather might even have contributed to John Kennedy’s narrow presidential success in 1960 because Democrats are more likely to get out and vote in better weather, even to the point of there being an adage “Republicans pray for rain”.

There’s a riot going on

Our ideal temperature is around 21 ºC. Studies show that as the temperature goes up so do tempers. The hotter it becomes the more violent crime increases: murder, assault, rape, and robbery. Spike Lee’s film “Do the right thing” nicely captures this association between rising temperature and simmering violence. Just look at when some of the most notable riots have happened: the 1981 Toxteth and Brixton riots, the 2001 summer riots of Lancashire and Yorkshire, the 2011 summer riots in ������Ƶ, and the 1965 Watts riot in August.

We have to be careful because a correlation doesn’t necessarily imply causation. It might be that people are more likely to consume alcohol on hot summer nights, or just more likely to be out and about. Laboratory studies however confirm that hotter temperatures really do make people tend to feel more angry, stressed, and irritable.

There is some suggestion that at very high temperatures tempers cool down. This idea makes sense because it can be too hot to do anything much. Researchers have proposed that rioting is most likely between 27º and 32ºC.

Whether weather?

It should be said that it has proved difficult to find clear and strong effects of weather on behaviour. Perhaps we shouldn’t be surprised.

Behaviour is complex and affected by many things, and weather is just one factor. It wouldn’t do from an evolutionary perspective if whenever the sun went in we all downed tools and went to sleep. We now spend much less time outside than even our recent ancestors did, so effects of the weather are bound to be smaller. And finally if there is some dimension that measures human behaviour, people will vary on it. I find it difficult to believe, but there really are people who prefer it dull, cool and wet to sunny, warm, and dry. Now the sun is out and so am I.

Trevor Harley
Emeritus Professor of Psychology
University of Dundee

Trevor is one of the world’s few psychometeorologists - working at the intersection of psychology and the weather. He has kept weather records for over thirty years, and maintains web pages on severe weather events in Britain which have proved very popular. Trevor carries out research into our memory for weather forecasts, for the weather itself, how the weather affects us, and why so many people are interested in the weather. In 2019 he published a book on with Routledge, available in Senate House Library. You can find out more about his work on .

Other books in Senate Library on weather and mood
 
Alter, Adam. . The Penguin Press, 2013
 
Bowring, Jacky. . Routledge, 2017. [E-BOOK]
 
Jones, Lucy. . Penguin Books, 2021.

Rosenthal, Norman. . Guildford Press, 1993.