I'm going to have to estimate that at no point since humans started keeping records was there ever a single day when rain did not hit some spot on the surface of our planet. If the earth did not experience rain before the Flood, then Noah's ark-building must have appeared especially foolish to his critics. Noah was warned about things not seen, which is perhaps a further indication that rain was not part of humanity's early experience. Likewise, the faith of Noah described in Hebrews 11:7 was especially strong. Every night a heavy mist came up and the streams and creek had a higher tide and that was what watered everything. Man and Woman in the Garden 4 This is the account of the heavens and the earth when they were created, in the day that the LORD God made them. This would limit the time of no rain from the third day until sometime just before man’s arrival on the sixth day – not the entire pre-Flood era. and no shrub of the field is yet in the earth, and no herb of the field yet sprouteth, for Jehovah God hath not rained upon the earth, and a man there is not to serve the ground, Study Bible. They had never seen rain before. I make this estimate based on having read that at any particular moment there are about 1,800 lightning bolts that strike our planet's surface somewhere, and usually these lightning bolts accompany heavy rain. The Bible indeed says that God had not caused it to rain upon the Earth, but also quickly adds, "there was no man to till the ground." That was the reason that people laughed at Noah when he told them that it was going to rain. The driest place on Earth is in Antarctica in an area called the Dry Valleys, which have seen no rain for nearly 2 million years. The day it didn't rain: BOM predicts the first EVER completely dry day across Australia as bushfires rage . One part of the story that has always intrigued me is that it had never rained on earth before the flood. Genesis 2:5 - "No shrub had yet appeared on the earth and no plant had yet sprung up, for the LORD God had not sent rain on the earth and there was no one to work the ground, (6) but streams came up from the earth and watered the whole surface of the ground."