The basis of element-day theory is that there are 8 days in the Vana'diel week. Each corresponds to one of the 8 elements. This is different from the real world where there are only seven days per week.
Firesday --> Earthsday --> Watersday --> Windsday --> Iceday --> Lightningday --> Lightsday --> Darksday
A good mnemonic for remembering the order is: FEW WILL Die. Also if you sort the Summoning Magic list after obtaining all Prime Avatars, it will sort by the order of the days.
- Each day lasts for 24 game hours from 0:00 - 24:00 (57 minutes, 36 seconds Earth Time).
- There are 25 Vana'diel days per Earth day, 175 Vana'diel days per Earth week (according to above).
Days and Spells
The days of the week have an influence on spell power. For instance, Lightsday occasionally increases light magic potency by 10% (Cure, Banish, etc) . Likewise, Darksday occasionally decreases Cure potency by 10%. All magic Astral Flow blood pacts are more powerful when used on the day corresponding to their element.
Fire melts Ice