I'm kind of curious which calendar people are using.
I know that the standard dates are a 368 day calendar in a variety of sources.
They agree on 5-day weeks.
WEG Era, 10 months of 35 days, plus 3 "festival weeks" and 3 "holidays" which all fall outside the months. Presumably, it matches the tapani pattern, which see below.
Essential Atlas uses a 12 month calendar...
368 days, 12 months (which means 30 8/12 days each), with 5th, 7th and 10th months certainly having at least 31 days. (Note, unless it's weird, it's unlikely to have more than 31 days in a month.)
I postulate the following pattern from that: 31,31,30,31,31,30,31,31,30,31,31,30
Empire day is given in this calendar as :5:25. (5th month, 25th day)
There is the Tapani Calendar, as well, from WEG's Lords of the Expanse... the pattern being: 35,35,1,35,5,35,35,1,35,5,35,35,1,35,35,5
Some gamers used to use a Pseudo-Julian calendar - the julian calendar simply numbers all days sequentially. Essentially, just numbering 1-368...
I myself am planning on using the Atlas calendar in my just starting AOR campaign.