First, Thanks, Jean-Yves, for the great suggestion on mapping the dates to the astronomical seasons!
FYI: Here is an explanation of the meteorological seasons. We took the easy way out since these are mapped to month number. 😀
https://www.noaa.gov/education/resource-collections/climate/changing-seasons
Regarding sorting, you can may want to map to a Season Number in the order that you want them shown, instead of the text.
Then, you can combine those two numbers into one column using a Text expression column.
For example, here is what this would look like in the data table, for the data that will be pivoted.
Then when you Pivot the data, use this combined Year-Season column to group the data.
Through a series of separate pivots and mapping, we created this look-up table. You could also manually create this by having a table with a list of every Year-Season in your data along with a corresponding label. Note the “\n” is added in the label so the season will be on a separate line.
Then this mapping withing the Pivot command is used to update the labels on the y-axis.
In any case, an interesting problem and we will think about adding this grouping to the Pivot!