Per user cache

Hello,

I have a dynamic website that i want to cache a piece of per user.
There
is a part of the page that makes a call to Yahoo Weather to pull the
information down. Instead of making that call for every page load (same
idea with google maps), i would like just to cache that fragment of the
page. However each user has a different zip so i need to cache this on
a
per user level.

Is this possible?

thanks
adam