Natural Cycles
Many Traditions include the natural cycles in their rituals, symbolism, and practices, often organizing their central narratives, festivities, and/or specific rites with periods of the year that seem most propitious for them.
For instance, in Christianity, the liturgical year, and the liturgy of the hours were organized in relation with the cosmic cycles of day and night as well as the seasons and their impact on human beings. Christmas is placed right after the winter solstice, creating a literal cosmic association between the event marking the birth of Jesus, in the heart of winter, when nights are longest, and the turning point when days start to get longer, and light starts to come back in the world.[1] Easter, symbol of the resurrection, occurs during the spring. As for the Diurnal cycle, mystagogy happened during the night offices, and rituals were coordinated with events like sunrise and sunset in complex ways.
We know there are more deaths during full moons, with moon cycles having various other effects, including changing the quality of trees's wood, and so we can assume there are impacts on humans. There are also more death and stress in the winter. All of these things are potential riggers for spontaneous Emergent Phenomena.
Day/Night
Seasons
Phases of the moon
Circadian rythms and bipolar disorder