  We conduct the largest ever investigation into the relationship between
meteorological conditions and the sentiment of human expressions. To do this,
we employ over three and a half billion social media posts from tens of
millions of individuals from both Facebook and Twitter between 2009 and 2016.
We find that cold temperatures, hot temperatures, precipitation, narrower daily
temperature ranges, humidity, and cloud cover are all associated with worsened
expressions of sentiment, even when excluding weather-related posts. We compare
the magnitude of our estimates with the effect sizes associated with notable
historical events occurring within our data.
