Hello, I was looking at the auspicious dates for my DOB and wondering what the element of the day represent for each day. I have strong earth. Does that mean it is not good if the element of the day is earth or fire? Thanks in advance!

Yes, that's correct. That is one of the conditions, as a Earth or Fire will make a Strong Earth even stronger. So it won't be as good as a Metal or Water or even Wood element day.

Of course, the auspicious date analysis will consider many other factors as well, but that is certainly one of the factor that will impact whether a day is suitable to you or not.