No. Generally speaking its every two weeks but really its when they feel they are ready for the next release.
I am not the "post police" here, but I see that you are new.
You should really re-think your post title when making new threads.
Your title suggests that there is a "new public beta release." Some on here will get upset about that, although the hostility on here is nothing compared to that on Reddit.
Here is a suggestion on a better thread title. You want to know when there will be a new release, so you make your thread title reflect it with a title like "When is the next public beta release?" (Note the question mark.) or " New public beta release: When is it?" (Again, notice the title denotes a question.)
This is not even taking into account others, that may hassle you for not searching first. We see MANY simillar threads, before and after EVERY release.
As the other guy said, it is typically every two weeks. It is usually on a Tuesday, as the first one is normally dropped on a Tuesday, right after a three day weekend like Memorial Day. They are usually dropped at 10:00am PST (For those NOT in USA, this means 10:00am in Cupertino, California, where Apple HQ is located.) I have seen it dropped much later in the day as well though. Keeping in mind the "normality" of releases, it is and always will just be speculation.