Perhaps you are referring to the traditional sun-sign astrology found in tabloids/magazines? There are claims that you can get much more precise by looking at ascendant-based astrology which varies down to the minute and lat/long of the place you were born. Or are you referring to both? Are there sources out there in the literature proving/disproving modern Astrology? There is this article on Gauquelin's Mars effect for instance -
https://en.wikipedia.org/wiki/Mars_effect