When Will the 3 Days of Darkness Be?

Sadlyrose writes:

I thought the Three Days of Darkenss is going be at the end of 3 and a half years. Is the last battle then, and after that, God will burn the world and bring his kingdom down?

MJJP replies:

No, it is a world without end, as we pray daily in the Creed which is a statement of Roman Catholic beliefs, taught to us by Christ and His 12 Apostles. 

The timing of the 3 Days of Darkness is not clear, except that we know they will occur towards the beginning of a year.

Look at the Warnings here:  The Warnings