On what day of the month did the Genesis flood begin when Noah was 600 years old?

Genesis says the flood began on the seventeenth day of the second month when Noah was 600 years old.

Genesis 7:11 gives a precise chronological marker: in Noah’s six hundredth year, during the second month, on the seventeenth day, the fountains of the deep burst open and the windows of heaven were opened. This date begins the flood chronology in the biblical narrative.

The account also provides later dates, including the date when the Ark came to rest and the date when the ground was dry. These details make the story unusually specific about elapsed time, even though ancient calendars and month names are not identical to modern calendar systems.

Readers sometimes confuse this date with the seventh day, when Noah is told to enter the Ark and the rain begins after the waiting period. Genesis distinguishes those events. The question asks for the flood’s stated beginning date, which is the seventeenth day of the second month.