I've not been to Abisko, but a few years ago I spent a ten days in
late August about twenty-ish miles west of there, just over the border
into Norway, and I don't remember midges or mosquitoes being a
particular problem. There were midges there, but much in much smaller
numbers than I'd expect in many parts of Scotland. Looking out at
Abisko from the train window as we went through, it looked like a
beautiful area.
Richard