In Genesis, on what date did the Flood begin when Noah was 600 years old?

Genesis says the Flood began on the seventeenth day of the second month in Noah’s six-hundredth year.

Genesis 7:11 gives this date while describing the bursting of the fountains of the deep and the opening of the floodgates of the heavens. The verse uses the calendar framework of the biblical narrative rather than a modern named month or a universally fixed calendar date.

The date is one of several precise chronological markers in the Ark story. Genesis later says the Ark came to rest on the mountains of Ararat on the seventeenth day of the seventh month, and that the earth was dry by the twenty-seventh day of the second month in Noah’s six-hundred-first year.

Because ancient calendar systems and month lengths differed, the date should not be converted into a modern day without additional assumptions. Its importance is primarily textual: it anchors the Flood in a carefully sequenced timeline.