["Psychology &Marketing, EarlyView. ", "\nABSTRACT\nDoes consumer perception of a sales event change if it falls across a calendar boundary (e.g., next month) versus within the current month, holding objective time constant? We investigate this question in the context of Cyber Monday, the global shopping event occurring the Monday after the U.S. Thanksgiving holiday. By analyzing over four million tweets spanning 11 years and conducting two controlled experiments, we observe that temporal borders, defined as calendar partitions separating a decision from an outcome, are associated with psychological discontinuities. Contrary to models of linear temporal decay, we identify a non‐linear border effect: crossing a temporal border is associated with increased subjective temporal distance; an event feels further away even when objective distance is held constant. This shift in subjective distance is, in turn, associated with more abstract construal of the event and a correspondingly stronger promotion regulatory focus. Conversely, events occurring within the same temporal period are associated with concrete construal and a prevention focus. This psychological shift is also associated with a behavioral outcome: consumers evaluating purchases across a temporal boundary express a significantly higher preference for products with promotion‐oriented attributes over prevention‐oriented ones. These findings introduce temporal borders as a factor which may influence the standard relationship between temporal distance and consumer judgment, offering guidance for optimizing the timing and framing of marketing communications.\n"]