How Much Does Rain Weigh?

A friend of mine likes to play with numbers. Calculations which speak of the wonder of the creation are of particular interest. My friend pointed out something that I had never really thought about. As I write this, it is raining, and we are supposed to get an inch (2.54 cm) of rain. How much does rain weigh?

For the sake of simplicity, let us assume we want to know the weight of an inch of rain on a square mile (2.58999 square km) of farmland. There are 5280 feet in a mile, so if an inch of rain, which is 1/12th of a foot, fell on a square mile of farmland the volume of water would be 5280 x 5280 divided by 12. That would be 2,323,200 cubic feet (65,785.698 cubic m). The density of water is 62.4 pounds per cubic foot (1000 kg per cubic m). The question is, how much does rain weigh? To calculate the weight of the water, multiply the cubic units by the weight for each cubic unit. That would come out to be 144,967,680 pounds or 72,483.84 tons (or 65,756,233.54 kg). That is for just one inch of rain. A foot of rain would weigh 12 times that much!

Rain is critical for our existence. We tend to take it for granted since we see it regularly in our day-to-day life. Perhaps we should pause and consider the wisdom build into a system that picks up many tons of water, lifts it high into the sky, and then pours it onto the land. Job said about God: “He does great and unsearchable things, wonders without number. He gives rain to the earth and sends water to the fields (Job 5:9-10).

The psalmist seems to have comprehended some of this design of God when he wrote: “Sing unto the Lord with thanksgiving; sing praise unto our God who covered the heaven with clouds, who prepares rain for the earth, who makes grass to grow upon the mountains. He gives to the beast his food …” (Psalms 147:7-9).
— John N. Clayton © 2019