Ready for Rainbows
From My Little Wiki
Rainy Day Outfit is very similar to the Ready for Rainbows outfit, however it contained wear for only one adult pony and was not sold in the U.S. In addition, the Rainy Day Outfit is more akin to actual raincoat rubbery material than the slick "rain slicker" fabric of the Ready for Rainbows set.
Version is a darker gold and a slightly different rubbery raincoat material.