According to Kotaku
, the Portal 2
DLC promised this summer is still coming this summer as long as you maintain a strict reading of the calender and Earth's position relative to the sun. Mid-September is the closest they can get to a firm date, and sure, that is technically still summer as long as "mid-September" doesn't actually mean January (because we all know time at Valve operates differently than in the outside world). I guess it's also possible they mean mid-September of 2012, as that would still technically be summer as well.