Colossal Comic #26, July 1963
That's Superman, Batman and Robin doing their skiing thing on the cover of Colossal Comic #26, at the Perisher Ski Resort.
Or so I like to imagine. Why?
It turns out that the publisher, KG Murray, was involved in the development of the Perisher Valley. Further, according to Wikipedia, "Murray Publishers...traded under the name of Perisher Ski Resort...(and) in 1995 Murray Publishers Pty Limited and the Alpine Australia Group Pty Limited merged to form Perisher Blue Pty Limited."
That's evidence enough for a legitimate leap of the imagination.