Thunderstorm Game
Ask the children to form a circle. Perform the motions to act out a thunderstorm. Make the children perform the actions with you. Wave your hands together back and forth to imitate the wind. Put out your hands and wave them down as you crouch to the floor imitating rain. Stamp your feet to imitate thunder. Say each word (wind, rain, thunder) as the children perform each action. You can add variation by having the children perform the actions on their own without your help or play a version of Simon Says with each child being Simon and asking the others to perform the rain actions.
Cotton Ball Cloud
Hand out a cotton ball to each child. This cotton ball will be a pretend cloud. Ask the children to touch and squeeze the cotton ball and answer how it feels. Hold out a small tub of water and ask each child to put the cotton ball in the water. Clarify to the children that this is what occurs when water disperses and goes up into the cloud where it is chilly and therefore turns into water. Place all the cotton balls on a flat surface and ask each child to pick one up, feel it and discuss how it feels. Explain that the water is sopping from the "cloud" because it got too heavy and therefore it produces rain.
Rain and Rainbows
Explain how rainbows are formed under just the right conditions of sunlight and rain. Go outside with the class on a sunny day and turn on the water hose. Lift it high so the water makes an arc, and show children how the light reflected off the water makes a rainbow, just as it does sometimes when it rains while the sun is still shining or just after a heavy rain, when the sun comes back out. Ask the students to tell you all the colors they see in the water hose rainbow. Return to the classroom and have the children draw pictures of the rainbows and rain on a sunny day.
Act it Out
Record different rain sounds and ask the children to help identify the different types of rain -- sprinkling, misting, raining, pouring and drizzling -- as well as lightning and thunder. Talk about the different types of rain gear. Bring different rain apparel to school and explain what each item is for. To end the class activity you can divide the class into two teams. Secretly ask one team to act out a type of rain and ask the other team to guess what type of rain it is.