Three studies demonstrated that mental simulations and affect are related to temporal changes in subjective confidence. In Study 1, students' confidence in their mid-term exam performance was lessened from the first day of class (3.5 weeks prior to the exam) to exam day, and confidence correlated negatively with upward simulations and negative affect. In Study 2, manipulated upward simulations produced low confidence and negative mood even when exams were viewed from a distance; students who were forced to think about upward simulations 1-month prior to the exam felt no more confident than did those on exam day. In Study 3, manipulated negative moods produced low confidence and more upward simulations when anticipating laboratory tasks, and again distal and proximal confidence did not differ. Discussion centers around reciprocal relations between mental simulations and affect, and a possibly integrative account of previous explanations.