In Genesis, God gave Noah seven days’ warning before the Flood began.
Genesis 7:4 says that rain would fall for forty days and forty nights, but that the Flood would begin after seven days. Noah, his family, and the animals were already inside the ark when the waters came. This distinction is often overlooked because the story combines a preparation period with the longer period of rainfall.
The seven-day interval belongs specifically to the biblical account in Genesis. Other flood traditions use different timelines and characters, so it should not be treated as a universal detail of every Noah-like flood story. The account presents Noah as obeying the command and completing preparations before the judgment begins.
The seven-day warning is separate from the 150-day period during which the waters prevailed. Those figures describe different stages of the narrative and should not be added together as though they represented one uninterrupted rainfall period.