Is it possible, as was once reported on National Public Radio, to have two sunsets in one day in Alaska?
Yes.......with some explanation needed.
Here's what the radio host was trying to grasp as he interviewed the National Weather Service employee in Kotzebue: As most everyone knows, between winter solstice (aprooximately December 21st in the Northern Hemisphere) and the summer solstice (around June 21st in the NH) the days lengthen, meaning the sunrise gets earlier each day and the sunset later. After the sumer solstice, the sunrise comes a little later each day and the sunset earlier, shortening the daylight length. So far no surprises, that happens everywhere (except on the equator). The farther from the equator one is, the greater the difference betweent the short winter days and the long summer days, giving Alaska its well known midnight sun.
So, it would not surprise you to think of a hypothetical place in Alaska where the sun rises at 1:04 a.m. and sets at 10:56 p.m. on a certain day, for a 21 hr, 52 minute daylight length. Oddly enough, this exact example would only occurr if the place in question was located on the same meridian (longitude line) that the standard time in use was based on. (More on standard time in the bonus section of the 2008 Alaska Weather Calendar.) In Alaska, the time zones have been consolidated from five to two, with the vast majotity of the state in one zone, based on 135W longitude, which runs through the Southeast panhandle. What this means is that the time of surise and sunset are not equally centered around midnight as in the example, but skewed, depending on how far east or west of 135W one is. Sun phenomena (and any stronomical phenomena) appear to our clocks to happen four minutes earlier for each degree of lattitude EAST of the standard time zone meridian one is located, or four minutes LATER for each degree of lattitude WEST of the standard time zone meridian. Most of Alaska is west of 135W and much of it by far. This means most of Alaska is one to two hours off local or "sun time" during the winter and two to three hours off when "Daylight Saving Time" makes us turn our clocks another hour ahead of sun time.
Now back to our example...sunrise at 1:04 a.m. and sunset at 10:56 p.m. Move the clock ahead and hour (as for being 15 degrees west of one's standard time meridian OR the application of Daylight Saving Time), and you get sunrise 2:04 a.m. and sunset at 11:56 p.m. Say the summer soltice is yet to arrive and the days are getting longer by a few minutes per day. In a few days the sunset will occurr after midnight, technically on the next day! So here is a day without a sunset. Suceeding days will have the sunset before the sunrise untill at some point, after the solstice when the days are getting shorter, the sunset just after midnight will be followed on the same calendar day by a sunset just before midnight, and there you have it: two sunsets on the same day! Totally an artifact of the use (and abuse) of standard time and/or Daylight Saving Time.