PPL theory may best be learned in an ancient procedure called talking in a group. A forum or some virtual know-all-see-all-Marjory-the-Trash-Heap never replaces brain activity.
First frame of reference is printed books, the internet is full of garbage and no quality assurance is visible and trust in posted threads, as more then just a hint where to find the real wisdom, is not advisable.
The wind variations, daily changes, geostrophical wind systems, Coriolis effects and height dependency there is a vast of very good met'books available. Weather is easy, once you get the basic physics and if you did not reach that point, you may get some lessons from a skilled, or discuss in a group (loop closed)