Valley Windworks is a power-generating station using tons of massive windmills, found at the southeast of Route 205. The wind energy is used to turn the turbine of the windmill to generate electricity. Team Galactic wanted to use this energy for their plans. This is the only place where you can catch a Drifloon on Fridays.
When you first visit this place, a Galactic Grunt should stand at the entrance. Battle him. However, when you battle him, he will go inside quickly and lock the door. You then have to get the Works Key from the Galactic Grunts at Floaroma Meadow.
After you get rid of Team Galactic, the man's daughter you met earlier will run back to him. The man will thank you and say something about a balloon Pokémon will come again. Refer below. The balloon Pokémon is Drifloon. It will visit every Friday after defeating Team Galactic.
Drifloon[]
After defeating Team Galactic, a Drifloon will appear in front of the Valley Windworks building. It will appear every Friday and will be gone the next day. So if you want to catch it, wait until Friday or change the day of your Nintendo DS. Drifloon will be at Level 22.
Trivia[]
In Platinum, after defeating Mars, the player can read a message on the computers here that refers to Mars as "the bringer of wars," Jupiter as "the bringer of contentment," and Saturn as "the bringer of aging." This is in reference to composer Gustav Holst's orchestral suite The Planets, in which the first, fourth, and fifth movements are titled Mars, the Bringer of War, Jupiter, the Bringer of Jollity, and Saturn, the Bringer of Old Age.