Rain is when liquid precipitation falls from the sky. Water droplets bump into each other as they gather in a cloud, and when one water droplet condenses, or combines with, another water droplet, it gets too heavy to stay suspended in the cloud and falls to Earth. Rain can also form from snow when the air below it is colder than freezing, or if there's more water than air in a cloud.

The resulting rainfall can do all sorts of things for people and plants: quench thirst, wash away dust and dirt, rehydrate crops, replenish aquifers, and make for a colorful rainbow. But it can also cause problems, such as floods and erosion. This year, a severe drought has caused widespread hunger and water shortages in Africa. In Ethiopia, Kenya, Somalia, and the Autonomous Region of Somaliland, 10.7 million people are in serious need of food.

For kids, a rainy day provides an excellent opportunity to learn about weather and science in an interactive way. Read aloud a book about the weather, or play a game that helps them understand it more deeply: for example, ask kids to write their name in the shape of a raindrop, or have them find something in nature that's different when it's raining. You can even turn the rain into a fun learning experience by creating a puddle and setting up a race for raindrops. On your mark, get set, go! (But make sure to watch out for thunder and lightning.)