Temperatures above or below a feel-good window of 12–21 degrees Celsius (54–70 °F) are linked to a marked rise in aggressive online behavior across the U.S., a new study finds. Analyzing billions of tweets posted on the social media platform Twitter in the U.S., researchers from the Potsdam Institute for Climate Impact Research found hate speech increasing across climate zones, income groups and belief systems for temperatures too hot or too cold. This indicates limits to adaptation to extreme temperatures, and sheds light on a yet underestimated societal impact of climate change: conflict in the digital sphere with implications for both societal cohesion and mental health.