New research looking at three and a half billion social media posts from tens of millions of individuals showed the very unshocking result that people are happiest on sunny clear days around 25C. Facebook and Twitter comments on those days used more positive, fun terms. Days below 20, above 30, that were cloudy or had a humidity above 80% put people in a less happy mood. So did terrorist events, and the effects of weather were pretty comparable. Temperatures that are below freezing put a real dampener on expressions of positive sentiment. (The next ice age is going to be no fun.)
Peak positive occurs in the mid to high twenties and on days with zero mm of rain.
Some people have a sunny disposition, others have cloudy faces and everyone over two knows what those expressions mean.
If our aim is to maximize human happiness and productivity, shouldn’t the UN Weather Control Committee (IPCC) be aiming to reduce freezing days and maximize the zone of 25C days on areas with the highest population density?
Judging by this awesome Hedonometer graph, during the hottest ever year of 2016, people were pretty happy.
Just cross checking that with the ENSO effect, perhaps we should also be working to increase El Nino years?
As for terrorism, conditions that were below freezing were comparable to the Sept 11 anniversary (in the US) and actual attacks, floods and earthquakes were even worse. Clearly, Daylight Savings time should only start, and never end. We all need the extra hour of sleep.
But keep in mind the y axis scale on the top graph. We’re talking about 2 percent less “happy thoughts” on a zero degree day. It sounds tiny, though on a national scale I expect it would translate to slightly higher cortisol levels, more stress, less health, and lower productivity.
Joe Pinkstone at the Daily Mail sees the cold threat: Cold weather is MORE depressing to people than a terrorist attack, claim scientists
Alan Martin at Alphr warns us about the heat: High temperatures make us hotheads: Study finds the weather impacts how we “talk” on Twitter and Facebook. “Blame it on the sunshine”.
A few caveats:
- Sarcasm and irony would skew these results and there “might” be some of that on Twitter. 😉
- Researchers think the results may underestimate the effect of weather because they are looking at a self selecting younger slice of the population which use Twitter and Facebook.
- They also acknowledge that their research was only done on the US where air conditioners are common, and a study of poorer nations may have an even more pronounced effect.
Dr Obradovich said: ‘We conducted the largest ever investigation into the relationship between meteorological conditions and the sentiment of human expressions. ‘We find that how we express ourselves is shaped by the weather outside. ‘Adverse weather conditions – hot and cold temperatures, precipitation, added humidity, and increased cloud cover – reduce the sentiment of human expressions across billions of social media posts drawn from millions of US residents.’ In particular, experts found that rain was associated with a more negatively expressed sentiment.
The study found positive expressions increase up to 20 degrees Celsius (68 degrees F), but stops short and declines as the temperature goes over 30 degrees (86 degrees F). Days with a humidity level of 80 per cent or higher were associated with negative expressions, as were days with a high amount of cloud cover.
Why does this research matter? From the Introduction in the paper:
Mood and emotional state support human physical, psychological, and economic well-being. Positive emotions are associated with improved physiological factors such as cortisol levels and cardiovascular functioning  and amplify cognitive performance and mental flexibility . They can also increase social connectedness and perceived social support  and may augment income and economic success . Emotional states can also be transmitted through social networks [5,6], amplifying the broad-scale effects of altered individual emotions.
Prior work suggests that environmental factors–and ambient meteorological conditions in particular–may substantively impact emotional state. However, previous empirical investigations of this relationship have found conflicting results. Early studies found large associations between meteorological conditions and mood [7,8] but were limited by small sample sizes and limited generalizability. A number of studies in the most recent decade have found small to negligible associations [9–11], while others document associations that vary across individuals [12,13], associations observed at high levels of aggregation , or associations that are contingent on other factors . A still more recent large-scale longitudinal analysis reports robust linkages between daily weather variation and reported well-being . Whether, and if so, how meteorological variables shape human emotions remains an open question.
h/t Climate Depot
Baylis P, Obradovich N, Kryvasheyeu Y, Chen H, Coviello L, Moro E, et al. (2018) Weather impacts expressed sentiment. PLoS ONE 13(4): e0195750. https://doi.org/10.1371/journal.pone.0195750 [Full free access]