The answer
There is no implication that rain did not occur prior to the great flood in Noah's days. The function of rain was described on the second day of creation in Genesis 1:6-8. Thus, God provided the use of rain and water prior to the creation of herbs, vegetation, animals, and mankind. We notice that each day of creation provided for the needs of the following days. The fierce flood described in Genesis 7:11-12 categorizes this vehement and relentless rain as a unique occurrence that had never taken place and would never be repeated: "In the six hundredth year of Noah’s life, in the second month, the seventeenth day of the month, on that day all the fountains of the great deep were broken up, and the windows of heaven were opened. And the rain was on the earth forty days and forty nights."Answered by His Eminence Metropolitan Youssef (opens in a new tab)