High school graduation dates in Alaska are much earlier than in other states because daylight hours are considerably longer from early May through September than they are in the contiguous 48 states. The summer visitor season runs from mid-May to mid-September.
Daylight hours in Alaska are longest on June 21st. There are 22 hours of daylight in Fairbanks, 19 in Anchorage, and 18 in the Southeast. From late May to late July, there is a light in the sky practically all night long. And for another month on either side of that period, it doesn't get dark until after 10 pm. The farther north a person goes, the longer the days are. In the Arctic region, the sun does not set for months at a time.