In Genesis, Noah and his family left Noah’s Ark on the twenty-seventh day of the second month.
Genesis 8:14–16 says that the earth was dry by the twenty-seventh day of the second month, and God then told Noah to leave the ark with his family and the animals. The account closes the ark episode with the creatures leaving so they can multiply on the earth.
This date should be distinguished from the seventeenth day of the second month, when Genesis says the ark came to rest on the mountains of Ararat. The two dates mark different points in the chronology: resting on the mountains and finally leaving the ark.
Genesis presents a carefully dated sequence, but it uses the calendar framework of its own ancient narrative. The passage does not identify the month with a modern Gregorian month, so converting it directly to a modern calendar date would be speculative.