The Day Out of Time marks the end of one solar cycle and the next.
The Day out of Time, which falls on July 25 each cycle, is the day before the new year.
The new year begins with July 26th and ends with July 24, only 364 days. The missing day is The Day Out of Time, giving the calendar 365 days.

This topic and others such as Day out Of Time is explained here, and perhaps you'll understand why it is celebrated.

Kin 223
Blue Lunar Night
I Polarize in order to Dream
Stabilizing Intuition
I seal the input of Abundance
With the Lunar tone of Challenge
I am guided by the power of vision
Castle 5: Green Central Castle of Enchantment
Wavespell White Wind

Full Moon
Full Moon