Yume has a full 24 hour night/day cycle, and each 24 hours is split into 6 hour “seasons”.

Summer

During “Summer” Yume is fully in the Kōkai (光界 ・こうかい (literal meaning is “Yang Realm” – like yang/light/positive energy – also reads as “spirits” so has dual meaning).

The entire world is full of life, energy, and the World Tree is completely energized and green.

Autumn

During “Autumn” Yume shifts from Kōkai to Seikai (星界・せいかい (literal meaning is “star realm”)). As the night draws near, the season of autumn comes in harsh red twilight. Everyone in the lower city goes inside awaiting the waters to rise back up to flood the city once again in darkness.

Winter

The world of Yume during late Autumn and all of winter is world of electricity, snow, rain, and darkness. Cyberpunk, flooded, dystopian, and hidden.

Spring

During “Spring” Yume transitions back to the Kōkai. The world is a world of blooming life. Light, life-giving rains wash away the night to reveal the city in it’s light. Plantation grows and gives life to the city.