This study analyzed the impact of the November 2015 Paris attacks on online hate. On the basis of social identity based theories of group relations, we hypothesized that exposure to online hate will increase in social climate of fear, uncertainty, and polarization. We expected that the increase of hate will be evident in the case of online hate associated to ethnicity or nationality, religion, political views, or terrorism, but not specifically other hate-associated categories. Societal level determinants of the temporal changes in online hate exposure have not been tested before. Our study utilized two cross-sectional, demographically balanced datasets to analyze the change in online hate exposure among Finnish young people aged 15 to 30. The first sample was collected in May–June 2013 and the second one in December 2015, only 1 month after the November 2015 Paris attacks. The results supported the hypotheses indicating that the quantity and quality of online hostilities are affected by the wider societal conditions. We suggest that more evidence of societal level determinants of online hostility is needed in order to understand online hate exposure rates at different times. •Online hate is a global phenomenon.•This study measured online hate before and after the November 2015 Paris attacks.•Online hate increased after the November 2015 Paris attacks.•Online hate took new forms and became related to a social climate of uncertainty.•The quantity and quality of online hate are affected by wider societal conditions.