The Alpo Balognia Calendar A is a calendar invented by Tim Forsythe in which the year is divided into four seasons rather than 12 months. The year is divided into four seasons: Spring, Summer, Autumn, and Winter, beginning with Spring (northern hemisphere) and each season has 91 days divided into 13 weeks of 7 days each. Each season begins on a Monday. The four seasons are followed by a feast period of 1 to 5 days, which does not belong to any week.