Have a question on my birthday in lunar calendar?

Hello my question is to know all about my signs I mean:

I know 24 of June of 1992 is year of the Monkey but I want to know why changes the animal of month because in calendar lunar I'm a snake in the month but if I was born on June I'm horse.

I'm a little bit confused.
PD: I was born at 16:00 I'm born on Monkey hour?