When are the clear out sales in lilycove in Pokemon emerald?

The clear out sales are actually triggered by the "Emerald Clock" (The clock you set up in your bedroom when you start the game.) After about every week or so in the game, an ad will appear on TV. This ad signals that the clear out sales are now available. This sale only lasts 24 "Emerald Clock" hours and goes away until the next "Emerald Clock" week.

Events like the Blender Master and the tide are all triggered by the "Emerald Clock" but last different amounts of time. (The tide is about six hours; Blender Master is triggered every week and lasts ten hours.)

***NOTE: Some clock-based events are ONLY triggered after you beat the elite four! Also, these events will not progress when your internal battery runs dry!***