Middengeard: Scales of War
The world of Middengeard is a disk of material covered by the dome of the sky and supported by columns of earth. The light of the heavens shines through at shifting points in the dome, partially illuminating the night.
A day begins when Wedell, the god of the sun, rises to do battle with Zoz, the god of darkness, across the sky. Nion, the goddess of the moon, strives to convice them of the futility of their fight. Day ends when one party gets the upper hand.
If Wedell is victorious, Nion intervenes to save Zoz and attempts to disarm Wedell. Zoz is also a god of trickery and takes the opportunity to strike down Wedell. Nion then gathers Wedell and brings him back to the Island of the Sun to be resurrected, fighting back across the sky to prevent Zoz from destroying his body.
If Zoz is victorious, Nion grabs Wedells body and brings it back to the Island of the Sun to be resurrected, fighting back across the sky to prevent Zoz from destroying the body.
Seasons change when Oromo, the god of death and winter, either approaches or retreats from the world. During the summer he is far away, tending to the souls on their ultimate journey. When a certain quota of souls amasses in Middengeard awaiting judgement, he ascends from the netherworld to judge and gather. Wedell must fly higher in the dome of the sky to prevent Oromo from weakening him too much, and so the world becomes colder. Days tend to be shorter as well since Oromo's presence gives Zoz a natural advantage. Once Oromo's court is held and the souls are judged he descends back into the netherworld and winter fades.
Measuring the passage of time:
Wedell and Nion's movements across the sky and Oromo and Wedell's ascents/descents are the most basic measurements of days and seasons passing. Some additionally break down time according to the activities of Dalgren and his daughters, Ulora and Elora (The god of nature and growth and the goddesses of wind and sky, clouds and rain, respectively).
A year is a cycle of seasons and is often irregular (a day itself is irregular, for that matter). Civilizations and organizations rely on mystics and sages to inform them of impending changes. Some scholars also claim to be able to predict changes based on the course of the heavens.
There is no common dating system and time is often measured from important events. The 5th year of the reign of the High King or 24 days from the end of the time of drought, etc.
Since there really isn't such a thing as a 24 hour period in this world, just assume that every mechanical instance of the distinction '24 hours' refers to the time between dawns, dusks, etc.