Time

According to the Book:

The people of Khorvaire mark the passage of time according to the standards developed by the Dragonmarked Houses(partially based on draconic measurements) and sanctioned by the rulers of Galifar almost a thousand years ago.
Days are 24 hours long, divided into day and night. Seven days make up a week, four weeks a month, and twelve months a year. The months correspond to the twelve moons of Eberron, and the prominent moon carries the name of the month in which its orbit brings it closest to the planet. The moons and months are tied to the dragonmarks by tradition and legend, as indicated on the table below. A thirteenth mark and moon once existed. It was a dark mark devoted to abilities concerned with death and the undead. Most consider the thirteenth mark to be nothing more than legend, but there are those who know better.

Marking the Years:

While a particular culture may count the years dating from some significant event in its past, the common calendar of Khorvaire is the Galifar Calendar. This reckoning of years was developed during the reign of Galifar the Dark, third ruler to sit upon the throne of Galifar. It counts from the founding of the kingdom to the present day. The dragonmarked houses adopted and use this calendar, as do the governments and peoples of @Khorvaire’s nations.

Days of the Week:

1: Sol, 2: Mol, 3: Zol, 4: Wir, 5: Zor, 6: Far, 7: Sar

Months of the Year:

1: Zarantyr (Midwinter), 2: Olarune (Late Winter), 3: Therendor (Early Spring), 4: Eyre (Midspring), 5: Dravago (Late Spring), 6: Nymm (Early Summer) 7: Lharvion (Midsummer), 8: Barrakas (Late Summer), 9: Rhann (Early Autumn), 10: Sypheros (Midautumn), 11: Ayrth (Late Autumn) 12: Vult (Early Winter)

City Of Daggers:

The events of City of Daggers begin on a Wir, the ninth day of Therendor in 998 YK.