A common calendar, on average 12 months of 30 days, 52 weeks or 365 days ( 365 days and 6 hours to be exact) , does not change your information as time passes, only sometimes political / social as holidays.
When faced with a calendar's information, is repeated year after year and only varies as to the phases of the moon relative to the days of the month and the name day moves one step forward. At this repetition adds one more day every four years, February 29 , the rest of the time, nothing changes.
With this scenario, we found on climate factors a way to make every day of a calendar, unique, and adding the variable of a city you like, every Coloudar will be different.
Climatic factors are specific due to its geographical location, is why every Colourdar is different depending on the city and the length of time you choose.