Be aware that I don't subscribe to the supernatural background of astrology or believe in anything supernatural. Also, the daily horoscope is clearly cow manure, and the rest of what I'll say applies solely to birth horoscopes.
I've had a long-standing interest in psychological personality profiling methods, and was quite intrigued when I discovered the MBTI several years ago. I later also came across the enneagram and a whole legion of what seem to be essentialy permutations of the MBTI working along different axes.
I was chatting with a few others about these kind of things a few years ago, and people mentioned their personality types and results from other psychologically founded tests right along with their birth horoscopes, which were supposedly rather accurate. Out of curiosity, I had mine done when someone offered to do it.
Well, in a number of ways it read quite like an INTP profile.
So I asked around, and well, as personality profiles, birth horoscopes seem to have better-than-random precision. That was just gut feeling at this point, however.
So I recently mentioned this to a psychologist I was talking with, and he mentioned that a few surveys had been conducted that apparently revealed a correlation. Obviously, there was much controversy about them at the time of the publication of each. I have the titles and ISBNs now (ISBN 3442307465, ISBN 3471774173), but I'm afraid they're written in German. :-)
So that's were I currently stand. There are indications that a correlation exists, and scientific method says that a theory is to be tested by its predictions. If such a correlation actually exists, there has to be a natural explanation for it, as far as I'm concerned. I won't be surprised to find that the world is a lot more complex than we perceive.
Remember (if I even have to remind you of all people) that correlation does not imply causality. I don't think the stars located millions and billions of light years away from earth have anything to do with our personalities; but something about their timing may well coincide with quite earthly processes we are not aware of.
I have no idea. All I know is that facts cannot be denied, so I want to find out more.
Makeshifts last the longest.