There is a series of German memes that open with 'Wenn dir klar wird', e.g.:
Wenn dir klar wird, was der Brexit wirklich bedeutet.
The meaning is clear:
When it becomes clear to you, what Brexit really means.
But there doesn't seem to be a subject in that first sentence in the German. Am I right in thinking that there is an implicit 'es'? So
Wenn es dir klar wird, was der Brexit wirklich bedeutet.
says exactly the same thing (and is grammatically 'more correct')?