Cloudsdale is the cloud city located in the skies somewhere above Equestria, and is the hometown of Rainbow Dash and Fluttershy. It is featured prominently in Sonic Rainboom and briefly in The Cutie Mark Chronicles. The name's suffix, "dale", is an old word for a valley or open river valley, but the name is also a play on the Clydesdale breed of horse. The city's buildings and general design take cues from Greek culture, which is appropriate as the myth of Pegasus originated from Greek mythology.
Rainbow Dash and Fluttershy visit Cloudsdale in the episode Sonic Rainboom in anticipation of the Best Young Flyer competition. It is revealed that Cloudsdale can only be accessed by Pegasus ponies. The whole city is made of clouds, which only Pegasus ponies can walk on. Twilight Sparkle uses magic to enable her non-Pegasi friends and herself to walk on clouds. Rarity, on the other hand, is given a pair of magical wings so she can fly along with them. The friends visit Cloudsdale and attend the Best Young Flyer competition to on cheer Rainbow Dash. The episode also shows facilities in Cloudsdale such as the large Cloudosseum, where the Best Young Flyer competition is held, and a weather factory where rainbows, snowflakes, and clouds are manufactured and distributed to Equestria.
A summer flight camp in Cloudsdale is the scene for Rainbow Dash's and Fluttershy's childhood flashbacks in The Cutie Mark Chronicles. In the flashbacks, Rainbow Dash stands up to some bullies who are making fun of Fluttershy's weak flying. Rainbow Dash challenges the bullies to a race, and at the beginning of the race, Fluttershy is accidentally knocked off a cloud and plummets to the ground. Her life is saved when she lands safely on a swarm of butterflies. Fluttershy gets her cutie mark when she realizes how much she loves the animals living on the earth below. Rainbow Dash's flashback includes the rest of the race. When she is winning, she realizes she loves speed and "winning". She miraculously performs a sonic rainboom and gets her cutie mark.
Hurricane Fluttershy portrays the annual task of delivering water to Cloudsdale, in order for the weather factory to produce the year's rain clouds for all of Equestria. When Ponyville is chosen for the year's delivery, Rainbow Dash and the town's other Pegasi must funnel water from Ponyville's reservoir by creating a tornado. Fluttershy is reluctant to help at first, on account of her weak flying skills and the taunting she endured at Cloudsdale's flight camp (as seen in a flashback). However, she eventually joins in the effort and delivers the final push needed to get the water to Cloudsdale.
In The Return of Harmony Part 1, when Discord tells Rainbow Dash that Cloudsdale would crumble without her and offers to restore her wings, Rainbow Dash is terrified. She accepts the offer and abandonds her friends, believing that she is needed in Cloudsdale.