San Francisco, Jul 7 (IANS): Hot weather may make people more aggressive but the rising mercury may not result in more angry tweets or hateful Facebook posts from the social media users, an interesting study has revealed. However, the first-of-its-kind research found that incidence of angry tweets is highest on Mondays.

The study by The Conversation that involved researchers from Macquarie University in Sydney, found that angry tweets increased as the weather turned cool.

As daily maximum temperatures rose, angry tweet counts decreased.

Hotter weather is associated with aggressive crime. However, it is not well known if similar relationships apply to online aggression.

"This study uses anger counts derived from Twitter posts (tweets) and assault counts in New South Wales, Australia, to investigate if they share a similar relationship with temperature, and to determine if online anger is a predictor of assault," said Heather R. Stevens from Macquarie University.

Published in the Sage Journal Environment and Behavior, the study indicated that while assault counts were higher in summer than winter, angry tweet counts were lower.

The study involved 74.2 million English-language Twitter posts from 2015 to 2017 in New South Wales.

About 2.87 million tweets (or 3.87 per cent) contained words or phrases considered angry, such as "vicious," "hated," "irritated," "disgusted," and "f*****".

On average, the number of angry tweets were highest when the temperature was below 15 degree Celsius, and lowest in warm temperatures (25-30 degree Celsius).

"The number of angry tweets slightly increased again in very high temperatures (above 35 degree Celsius), although with fewer days in that range there was less certainty about the trend," said the study.

On the 10 days with the highest daily maximum temperatures, the average angry tweet count was 2,482 per day.

Of the 10 coldest days, the average angry tweet count was higher at 3,354 per day.

According to the authors, 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," said the report.

"Angry tweet counts were inversely associated with assaults, with an increase in tweets signaling decreasing assaults," the authors wrote.

There are several plausible explanations for the dissimilarities including the impact of temperature on behaviour, socio-demographic differences, and data collection methods.

The findings of this study add to the growing literature in social media emotion and its relationship with temperature, said the authors.