Open question, re: Noach

Reading this portion, Genesis 6:9-11:32, reminded me of a question I have not found a good answer to….yet.   Maybe some of you have thoughts you are willing to share.

The Noach portion has clear lessons for those living in the last days, and I think some explicit details are meant to be unlocked and understood.  So, the recurring question:  What is the significance of the VERY specific dates in the text regarding the day it began and the day it ended?  Lengths of phases, I.e. rain for 40 days, dry for 40, etc are important, but the specificity of dates is a bold highlight in the text.  What is the relevance?