As referenced in Article 8, sections 4 and 5, of the USPS-NALC and USPS-APWU national agreements, the December period (during which penalty overtime regulations are not applicable) consists of four consecutive service weeks. This year, the December period begins Pay Period 26-15, Week 2 (December 5, 2015) and ends Pay Period 01-16, Week 1 (January 1, 2016).

— Labor Relations Policy and Programs,
Labor Relations, 10-15-15

Source: Human Resources