The server itself is set to a 5 hour day. This is mechanically so that it staggers the day/night schedule. We would have preferred something like an 11 hour or 13 hour day to accomplish this but, those don't exist.
Each IRL day = 2 IC days
Yes I know... it doesn't line up exactly with mechanical days.
IC days end at about 3pm EST
But why 3pm?
This separates the day players and night players and MOSTLY prevents the day change happening while players are online to prevent "belief" issues. Keeps things a little more organized. This means if you play during the morning or nights only IRL, you can RP out the day cycles as you see them and the days will for the most part seem close to as realistic as possible given the shortcomings of the games mechanical clock features.
But why not have the days as they are mechanically?
Otherwise, the lore ICly will have progressed in 1 month IRL, 148.8 days... or about 4 1/2 months. Thats a rather large time difference.
Why use 5 hour days instead of 12 hour days like usual?
We wanted to stagger the day/night schedule. People generally play at roughly the same times every day IRL. With a 12 hour day, this means they would always be playing during the day or at night. With settings as they are, this could get annoying, fast. So, we chose the 5 hour days.