Baby, It's Cold Outside [Complete]
Episodes 41 and 42 of My Little Pony and Friends, from 1986
The Ponies are delighted as snow falls in summer, not realizing that it's a plot by the Penguin King to freeze Ponyland and destroy those that can't survive the cold.
(Please, please please PLEASE support the official release. Buy the DVDs. I did, you should too. It's good stuff. Show Hasbro your support so they'll keep making more of these!)