Water vapor doesn't have the weight until it becomes larger droplets to fall to earth

 So, in a vapor form the individual water particles are light enough individually to stay aloft sometimes in the air. However, where I live fog often happens where it comes right down to earth along the northern California coast and wets the ground often at night as the moisture in fog hits the ground and makes roads more slippery mostly during the night. However, in this fog form unless it hits the ground it stays in the air too and could eventually turn into rain clouds. But, what usually happens here is that it moves inland and the drier air inland simply sucks the moisture eventually out of the high or low fog as it moves inland. But, this also cools the coast and far inland up to 20 to 30 miles from the ocean too.

So, thinking about water vapor not having weight like when your kettle is blowing steam out the top from boiling might make more sense. Often in the winter when our central heating system dries out the air I will take a cast iron pot and put it on the stove to wet the air with steam so it isn't so dry. So, there is a similarity of steam to water vapor because in essence they are the same thing as clouds just in a smaller form often in your kitchen.