THE ARKANIAN CALENDAR
The manual descriptions in the "Calendar" paragraph leave out numerous months and the winter months are not shown in proper order. The appendices show the descriptions of the gods and they are in the actual monthly order. I tested this by having my party sleep away an entire year. The following is the correct order of the year and the list of the days in order. The five dark days fall between between the last month and the first. All regular month names are "roughly" since that's how the manual describes Praios. The seasons are exactly how described in the game. The link above no longer works.

Praios Sun, Might and Rule (Summer July)
Rondra War, Lightning and Thunder (Summer Aug)
Effered Rain, Sea and Voyage (Summer Sept)
Travia, Hospitality and Marriage (Fall Oct)
Boron, Sleep and Death (Fall Nov)
Hesinde, Arts, Science and Magic (Fall Dec)
Firun, Hunting and Winter (Winter Jan)
Tsa, Renewal and Youth (Winter Feb)
Phex, Trade and Band of Thieves (Winter Mar)
Peraine, Seeding and Healing (Spring Apr)
Ingerimm, Fire, Skill of Iron Work (Spring May)
Rahja, Love, Ecstasy and Wine (Spring Jun)
All months are 30 days.
-- 5 unnamed dark days.
(30*12)+5=365 days

The weekdays, in order, are:
Praiosday
Rohalday
Fireday
Waterday
Windsday
Earthday
Marketday
(I had to guess that Praiosday is the first day of the week but the order is correct)