This concept is used passively inside the game of HoA. There are future ideas though for timed boosts or penalties based on the dates given. Whether they will be implemented, and when is unknown at the time...
The Ardanian Calendar
The Ardanian Calendar is a rather new addition to the kingdom. It was created by the seers of Garuta, who have worked out very sophisticated methods of determining the exact length of each year in current times. A year is approximately three hundred and sixty days in length. Days in excess of three hundred and sixty are declared vacation to all his Majesty’s subjects, known as The Days of Krolm. Recently, the time keeper's building has been moved to Lormidia to be in an atmosphere more suited for those that work inside; an atmosphere of magic and intellect. All three hundred and sixty days are divided into six months. Each month consists of six weeks of ten days. Each month is dedicated to one of the lesser Deities.