According to Genesis, in which month did Noah enter the Ark?

According to Genesis, Noah entered the Ark in the second month.

Genesis 7:11–13 dates the beginning of the Flood to the seventeenth day of the second month in Noah’s six-hundredth year. The passage says that Noah, his family, and the animals entered the Ark on that day, after which the rain began.

The second month is not the same point as the seventh month mentioned later in Genesis 8:4, when the Ark came to rest on the mountains of Ararat. The narrative uses these numbered months to mark the Flood’s progression, which is why the two details are sometimes mixed up.

Biblical calendar systems were not identical to the modern Gregorian calendar. Without knowing the precise calendar convention intended, “second month” cannot be assigned confidently to a modern month such as February or March. The stable answer is the numbered month given by Genesis.