"Rainy Day!" is an episode of Oobi from the first season.
When the rain spoils their plans, Oobi and Kako reluctantly join Uma in her search for a rainbow. The three enjoy catching raindrops and splashing in puddles. Uma finally finds a rainbow. — ABC Television
Oobi and Kako are about to play outside. They hear the sound of rain and realize that they must stay inside. Uma appears in a raincoat and tells the boys that she likes rain because it creates rainbows. As she marches outside in hopes of finding a rainbow, Kako tells her that it is not easy. Uma is determined to find one anyway. Oobi and Kako reluctantly agree to help her after she begs them to do so. They put on their raincoats and walk outside, where Uma tries to catch raindrops. Oobi and Kako join her and end up having fun.
The boys try to run inside when Uma spots a puddle and asks them to splash in it with her. They agree and enjoy themselves once again. The amount of rainfall begins to decrease and the sun soon appears. Uma tells herself that there is no chance of a rainbow now that the rain has stopped. As she sadly walks toward the house, she discovers that a beautiful rainbow has appeared by the fence. She tells the boys to look at it. Grampu walks outside to admire it as well. Kako later appears in an interview segment, asking preschoolers if they like the rain. Afterwards, the children play a dance game in which they do the "Rainbow Dance". The three moves are: the rain, the sun, and a rainbow. The episode ends when it begins raining again and they run around excitedly.