The literature on populist attitudes frequently makes one of two assumptions: populist attitudes are either stable or unstable. However, few studies have examined these diverging assumptions empirically. We use panel data collected over six panel waves between 2017 and 2021 in Germany to assess the stability of populist attitudes. Integrating inter-individual stability (variable-centred) and intra-individual stability (individual trajectories), we find that populist attitudes are neither fully stable (trait) nor fully flexible (state). For example, some respondents constantly changed their view on populism while the attitudes in one out of three individuals remained stable. We also explore empirical consequences and find that populist attitudes are more closely linked to vote choice when they are stable. Accordingly, we argue for a more nuanced understanding of the dynamics of populist attitudes, both at the variable and individual levels, where these attitudes are stable and consequential for only a subset of individuals.