Analysis of 300 million tweets shows tweeters are happiest on Sunday morning and gloomiest on Thursday evening.
Researchers from Northeastern University and Harvard University studied the characteristics of tweets over one year.
Daily variations showed the early morning and late evening having the highest level of happy tweets.
Weekly trends showed weekends happier than weekdays with the peak in the overall tweet mood score observed on Sunday mornings, and the trough on Thursday evenings
Geographic variations showed the west coast happier in a pattern that is consistently three hours behind the east coast. Overall, the west coast of the US were happier than the east coast.