•The Big Five traits predicted everyday personality and affect states in five cultures.•Individuals manifested the positive poles of the Big Five traits more in situations with greater autonomy.•The relationships between traits and positive affect were generally fully mediated by personality states.•Cultural differences in the strength of the trait-state relationships were limited.•Cultural differences were not due to individualism–collectivism, dialecticism, or cultural tightness. Consistent with trait theory and the density distributions approach (Fleeson, 2001), the Big Five traits predicted personality and affect states across 20days in five cultures. Perceived autonomy in everyday situations did not moderate the strength of the trait-state relationships, but individuals manifested the positive pole of the Big Five traits more in situations in which they perceived greater autonomy. Consistent with the dynamic mediation model (Wilt, Noftle, Fleeson, & Spain, 2012), the relationships between trait extraversion, agreeableness, and openness to experience and positive affect states were generally fully mediated by the associated personality states. Cultural differences in the strength of the trait-state relationships were limited and were not accounted for by cultural differences in individualism–collectivism, dialecticism, or tightness.