I don't think any other (non-verbose) options encapsulate what summer means with the same specificity. Q2/Q3 includes a far longer span of time, mid-2015 covers a 4 month period that covers a significant portion of spring and doesn't cover the entirety of summer, and I fear that all other simple options would suffer the same fate.
Considering the vast majority of computer users and potential Microsoft customers reside in the northern hemisphere, I don't think there's any problem with using summer as a timeframe.
> I don't think any other (non-verbose) options encapsulate what summer means with the same specificity.
You mean lack of specificity?
From what I gather, it's at some point during the middle of my winter.
Of course, nobody actually remembers when the seasons start and end (though we just check wikipedia), while most people definitely know the order of the months. And even after checking, "this summer", is really a 3.5 month period, which is still as vague (if not more) as "mid 2015".
Considering the vast majority of computer users and potential Microsoft customers reside in the northern hemisphere, I don't think there's any problem with using summer as a timeframe.