On what day of Noah’s 600th year did the Flood waters begin, according to Genesis?

According to Genesis, the Flood waters began on the 17th day of the second month of Noah’s 600th year.

Genesis 7:11 supplies this unusually precise date. It says that the fountains of the deep burst open and the windows of heaven were opened on that day, beginning the Flood described in the narrative.

The date is part of a sequence of chronological notices in Genesis. Later, the ark comes to rest on the mountains of Ararat on the seventeenth day of the seventh month, and the earth is dry by the twenty-seventh day of the second month in Noah’s 601st year.

The biblical calendar’s exact correspondence with modern calendar systems is uncertain, so the date should not be converted into a modern month without additional assumptions. The canonical answer is the textual date itself.