Absolute pitch (AP) judgments, by definition, do not require a reference note, and thus might be viewed as context independent. Here, we specifically test whether short-term exposure to particular intonation contexts influences AP categorization on a rapid time scale and whether such context effects can change from moment to moment. In Experiment 1, participants heard duets in which a “lead” instrument always began before a “secondary” instrument. Both instruments independently varied on intonation (flat, in-tune, or sharp). Despite participants being instructed to judge only the intonation of the secondary instrument, we found that participants treated the lead instrument’s intonation as “in-tune” and intonation judgments of the secondary instrument were relativized against this standard. In Experiment 2, participants heard a short antecedent context melody (flat, in-tune, or sharp) followed by an isolated target note (flat, in-tune, or sharp). Target note intonation judgments were once again relativized against the context melody’s intonation, though only for notes that were experienced in the context or implied by the context key signature. Moreover, maximally contrastive intonation combinations of context and target engendered systematic note misclassifications. For example, a flat melody resulted in a greater likelihood of misclassifying a “sharp F-sharp” as a “G.” These results highlight that both intonation and note category judgments among AP possessors are rapidly modified by the listening environment on the order of seconds, arguing against an invariant mental representation of the absolute pitches of notes. Implications for general auditory theories of perception are discussed.