The UPSC releases its examination calendar approximately once a year. This calendar outlines the schedule for various exams, including the Civil Services Preliminary, Main Examination, and interviews. The official calendar is usually published on the UPSC website around February or March each year, detailing important dates for application submissions, examination dates, and results announcements. Candidates are encouraged to regularly check the UPSC official site for any updates or changes in the examination schedule, as adherence to these deadlines is crucial for their exam preparation.