Fatima Portugal - 1917

On October 13, 1917 a crowd believed to be approximately 70,000 in number, gathered at the Cova da Iria fields near Fátima, Portugal. According to many witness statements, after a downfall of rain, the dark clouds broke and the sun appeared as an opaque, spinning disk in the sky. Many skeptics believe that the event was natural and meteorological in nature. But, how does one explain that the event occurred at the exact time predicted by three young children ?