In this study, I will introduce the concept of affective atmospheres previously developed by Anderson (Emot Space Soc 2:77-81, 2009) and Anderson and Ash (2015), to explore young social media users' articulated experiences of aggressive behaviour on a popular social networking site in Sweden. This concept opens up for inquiring into bullying, and other aggressive behaviour, as encounters, not only between humans, but also with non-human bodies, and the potentialities to act and the affective states that such meetings enable. In this way the paper contributes to bullying research on school climate and social atmosphere. The paper applies an affect theory approach to atmosphere to explore the importance of different materialities for the production of feelings and emotions surrounding the everyday articulations of hate among these users. The findings suggest that hate, in this context, works through a sexualized and gendered affective regime, which enforces a chrononormative logic, through which temporalized norms are tied to notions of age and bodily growth, that is, through heteronormative expectations of femininity, masculinity, sexuality and age-appropriateness. I found that affordances such as anonymity facilitated and intensified the circulation of hate, feeding into an atmosphere of constant risk. However, I also detail how affordances such as anonymity and hyperlinking, and practices such as hashtagging, enabled expressions of friendship, love and support, thus counter-balancing an atmosphere of hate and enabling it to become bearable for certain targeted users. In this context, sexualized aggression is normalized and expected, but nonetheless also troubled and resisted by these young users. By applying the concept of atmosphere, the paper sheds light on the affective workings within social online settings that become saturated with sexualized and aggressive practices, where certain users become repeated targets of such practices.