[en] Mindfulness has been studied as a momentary state and as an enduring trait, yet little research has reconciled these accounts. We draw from Whole Trait Theory (WTT) to conceptualize (the descriptive side of) trait mindfulness as a person-specific density distribution of mindful states. In preregistered secondary analyses of three samples – daily diaries with adolescents (1,505 observations) and experience sampling with undergraduates (1,889 and 3,962 observations) – we examined density distributions of mindful awareness and mindful nonjudgment states. Consistent with WTT, mindful states (a) fluctuated considerably within persons and across contexts, and (b) density distributions of these states were stable over time. WTT offers precision to the construct of trait mindfulness while emphasizing its sensitivity to contexts and its connection with mindful states.