At launch, the game will start in 1790 and runs until 1830 before resetting. This time is covered over the course of a 5 year real life time span. In order to allow people who play at the same time every day to experience a full 24 hour day in game, we offset our math slightly by dividing the day by 8.x for real time.
The Calendar provides a button (upper right hand corner) that will convert from game time to your local time zone for you so you can schedule in world events in real world time.
Please also see our Knowledge Base article for the Calendar: