The first holiday of the year is Bright Soul’s Day, which takes place in the middle of Olarune (February). It celebrates the end of winter with a commemoration of all those who have given their lives in defense against darkness. Because the church prefers to cremate rather than bury bodies, the faithful do not have graves to furnish; instead, churches keep records of those who have joined the Flame on stone tablets, which are washed with holy water on this holiday.
Source: Cultures of Thrane
The 18th of Olarune is Bright Souls Day, when followers of the Silver Flame celebrate and commemorate those they have lost. It’s a deeply personal holiday, so every community observes it slightly differently. Generally, those who have lost loved ones recently will hold small ceremonies to remember them. It’s also common for communities to gather and spend the day together, exchanging stories and memories, and thanking those who passed for the future they played a part in. An uncommon practice on Bright Souls Day is avoidance of artificial light. Those who practice this tradition spend the day only under the light of the sun and accept the coming of the night in respect for those who faced the darkness and never resurfaced.
Source: Sarhain's Guide to the Silver Flame
As the dark days of winter draw to a close, the Purified celebrate the lives and the sacrifice of those who gave their lives to fight evil and protect the faithful.
Source: Eberron Campaign Guide
As the dark days of winter draw to a close, the Purified celebrate the lives, and the sacrifice, of every follower of the Flame who died fighting evil and protecting the faithful. Those who have lost relatives in the past five years perform the funeral rite on the gravesite (or in a church, if the gravesite is not accessible), while everyone else sings paeans of gratitude to the fallen. On this day, the Purified are forbidden to use artificial or magical light sources, except in emergencies. They enjoy the day and accept the fall of night, as those who have died experienced life and did not fear death.
Source: Faiths of Eberron