Hammer, Shield, and Ring
The Dvorgr Calendar is a system based on days, Turns, and Holds. A Turn is equivalent to a year; each turn is the time from the beginning of Spring until the end of Winter. A Hold marks the time that a given House of the Seven Houses serves as council for the King; a Hold is seven Turns long. Thus, to go completely around the Dwarven calendar one cycle takes forty nine years.
Sometimes, dwarves will break up a Turn by the season; there are approximately 95 days in the Fall and Winter seasons, and approximately 85 days in the Spring and Summer months. This varies from Hold to Hold as the different clans in each Hold have differing agendas, and some may value a longer planting season whereas others might value more time for underground activities.