Cycle Festivals were prominent festivals in the later BR era and throughout the PR, when the realm was host to four-year long cycles of Seasonal activity.
History
Agriculture depends on predictable weather, and before the War of Essence in 650 BR, weather could only be prepared for, not predicted. Farming was fare more stressful, and harvests could spoil in a matter of days in the elemental chaos surrounding the realm caused droughts or periods of sudden frost. However, after 650 BR, the seasons of the plane settled into a comfortable pattern: Every four years the climate would shift considerably.
As such, Cycle Festivals were held every four years to celebrate either the end of a very successful harvesting season, or to celebrate the end of a long winter or summer.
Example Festivals
See also: Nestle#Cycle Festival