How do you figure out someone's rising sign?

Question

Whenever I look at the sites online my gf's rising sign about half of the answers turn out to be Cancer or Gemini.

Answer 1

cancer is never very strong, when on the ascendant.....so that could be the confusion

Answer 2

You need to know the exact time and place of her birth.

Answer 3

It depends on what time she is born! :]

EDIT: Wow, her birthday is one day before mine! X] I'm December 23, 1988 at 11:15 AM in San Francisco and my rising is Pisces. Your girlfriends rising sign is GEMINI! Hope that helps!