The Bible describes a mist that rose up from the Earth ~ such as seawater being drawn toward a passing (fortunately) asteroid might produce.
It simply didn't state that it didn't rain.
GEN 2:5 And every plant of the field before it was in the earth, and every herb of the field before it grew:
for the LORD God had not caused it to rain upon the earth, and there was not a man to till the ground.
GEN 2:6 But there went up a mist from the earth, and watered the whole face of the ground.