DuracellEnergizer said:
It you're willing to settle for a formerly-ostensibly-canon-thing-which-is-now-a-completely-non-canon-thing from the EU, then a year in the SW Galaxy is either ten months long or twelve months long (as one would expect from the EU, there's a lack of consistency).
I'm assuming all "years" are based on the Imperial definition of how long a year is, since a year is based on a planet revolving around its star and would depend on the planet assuming it works the same as earthly years. I would imagine there is some sort of official Republic or Empire time-keeping system in place