How many days and nights did rain fall in the Genesis flood story involving Noah's Ark?

In the Genesis flood story involving Noah's Ark, rain fell for 40 days and 40 nights. Genesis 7:12 gives this duration after Noah and the other ark occupants enter the vessel.

The number 40 has recurring importance in biblical narratives. Other examples include Moses' 40 days on Mount Sinai and Israel's 40 years in the wilderness. In the ark account, however, the 40-day period refers specifically to the continuing rain, not necessarily to the entire time that the floodwaters covered the earth or to the complete length of Noah's stay aboard the ark.

This distinction matters because Genesis describes a longer chronology: the waters remain for an extended period, and the narrative tracks dates as they rise and recede. Thus, “40 days and 40 nights” is the canonical answer for the rainfall, not the total duration of the flood episode.