is there ever a time when the catholic where skull caps?

Answer 1

Yes.

The skullcap worn by the Catholic clergy is called a zucchetto.

All Catholic clergy are entitled to wear the zucchetto.
+ The Pope's zucchetto is white
+ Cardinals are red
+ Bishops are purple
+ Priests and deacons are black

Some think that Zucchettos go back to when clerics shaved the center of their heads into a tonsure. Zucchettos would help keep thier heads warm.

http://www.newadvent.org/cathen/15765b.htm

Out of respect, a Catholic would wear a Jewish skull cap, kippah in Hebrew or yarmulke in Yiddish, when attending a Jewish religious service.

With love in Christ.