The ancient Greek festival honoring Cronus was the Kronia.
The Kronia was celebrated in Athens on the 12th day of Hekatombaion, the first month of the Attic calendar. That date fell roughly in late July or early August, so the festival is better described as a mid-summer or first-harvest observance than as a fixed solstice celebration. It was also known in parts of Ionia, where the month Kronion took its name from the festival.
Kronos, or Cronus, was associated with the mythical Golden Age, a time imagined as free from hard labor and social exploitation. During the festival, enslaved people and free citizens could dine and celebrate together, temporarily reversing ordinary social expectations.
Kronia is sometimes compared with the Roman Saturnalia because both involved feasting and temporary social leveling. They were related by theme, but they were distinct festivals in different cultural settings.