Friday the 13 is considered unlucky. There are varied why from folk lore.. but most people connect Friday the 13 with being unlucky.

Mary appeared on the 13. And for 5 months told the three children to come back on the 13.

Today is Friday the 13 the feast of Our Lady of Fatima.. I think Mary choose the 13 to show that history is not govern by the stars or that Friday the 13 is not to be considered unlucky. That Jesus is Lord of History.

So part of the reason Mary appeared on the 13. Was to teach us not to fall for something as silly as thinking Friday the 13 is unlucky. In fact Mary redeemed poor Friday the 13 and made it a day of great joy.

With Mary there are no longer any unlucky days only days of Great Joy.

Mary to the three children ‘Come here here on the 13 for the next 5 consecutive months.’