I want to find the 2nd highest block average. In the formula below, I am find the 3-hour block averages.

3-hour block average refers to finding the average of A1:A3, A4:A6, A7:A9 etc.

AVERAGE(OFFSET($G$3,(ROW($G3)-1)*3,0,3,1))

However, I don't want to find the average of the 3-hour block averages. I want to find the maximum 3-hour block average. How would I do that?

I've tried adding a LARGE in front, but since the AVERAGE already finds the average of each 3-hour block, that doesn't work.

Example:

I would average 3.6, 2.6, and 1.2 and get one value, then Calib, 2.5, 1.8, etc. When I reach the end, I want to find the second highest 3-block average.