The link between hot weather and aggressive crime is well established. However, can the same be said for online aggression, such as angry tweets? And is online anger a predictor of assaults? A research study just published suggests the answer is a clear “no”. We found angry tweet counts increased in cooler weather. And as daily maximum temperatures rose, angry tweet counts decreased.



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Algorithms are watching you on Twitter


When you publicly post, comment, or even upload a selfie, an algorithm can scan it to estimate your mood (positive or negative) or your emotion (such as anger, joy, fear, or surprise).

This information can be linked with the date, time of day, location, or even your age and sex, to determine the “mood” of a city or country in near real-time.




Hot-headed when it’s cold outside





So why the opposite patterns? We propose two possible explanations.

First, hot and cold weather triggers a physiological response in humans. Temperature affects our heart rate, the amount of oxygen to our brain, hormone regulation (including testosterone), and our ability to sleep. In some people, this in turn affects physical aggression levels.

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Hot weather means more socialising, and potentially less time for tweeting. Photo by Dugba Cauley-Hushie / Unsplash

Second, weather triggers changes to our routine. Research suggests aggressive crimes increase because warmer weather encourages behavior that fosters assaults. This includes more time outdoors, increased socializing, and drinking alcohol.

Those same factors – time outdoors and more socializing – may reduce the opportunity or motivation to tweet. And the effects of alcohol (such as reduced mental clarity and physical precision) make composing a tweet harder, and therefore less likely.

This theory is supported by our finding that both angry tweet counts, as well as overall tweet counts, were lowest on weekends, holidays, and the hottest days.




Our study did not consider why these two groups differ in response to temperature. However, we are currently researching how age, sex, and other social and demographic factors that influence the relationships between temperature and aggression.

Hot weather means more socializing, and potentially less time for tweeting. This explains why most angry tweets can be seen when it is cold. Tweet this

Twitter Monday blues




  • sporting events including the Cricket World Cup in 2015.

Twitter in a warming world

Our study was limited in that Twitter users are not necessarily representative of the broader population. For example, Twitter is a preferred medium for politicians, academics, and journalists. These users may express different emotions, or less emotion, in their posts than other social media users.




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