Averaging Most Recent Contiguous Run of Cells

I am creating a production schedule for a local micro brewery in town. They produce a handful of beers year round, continuously, and other beers during certain times of the year only. I have a usage table where we plot each week's use for each type of beer.

My problem arises when I try to find the average use for the most recent seasonal run of beers. To clarify, the seasonal beers will have data for several weeks in a row, and then several weeks of blank cells, followed by another group of weeks with data. I need to be able to reference the most recent group of cells to run calculations (like average use, growth rate etc). For instance, they brew a wheat beer during the summer months only. So we will have data from May 1 to Sept 1 for example, and blank cells for the remainder of the year. The brewery wants to see what last summer's average use was, and the summers prior to that should not be included (or at least given less weight).

So how do I determine that most recent run of weeks? I've tried areas() but that does not seem to do what I'm intending. I'm having trouble wrapping my head around what equations I should use for this. Thanks in advance for any help.

This works perfect. Thank you so much!!