I live in the north part of the north hemisphere. It's bright outside the entire 24 hours for almost a month during summer. I use a sleep mask to combat it and the last 5 years I feel like I regained sleep during the summertime. Last year I purchased a Manta Sleep mask and they are next-level good. Total darkness and really easy on the face. I have no affiliation with the brand, just a really happy customer of theirs.