White Nights in Portland

One of the aspects of Portland that took us by surprise (though quite unreasonably since it’s not as if we were ignorant of the phenomenon) was the length of the days. Afternoons seemed to stretch on endlessly, and although our body clocks should have been telling us it was two hours later than clock time (we’d traveled back in time by two time zones), it always seemed an hour or two earlier by sun time. One night as we returned to our third-floor hotel room after a late supper or shopping excursion, my husband commented on how incredible it was that we could look out our (west-facing) window from a lighted room and still see a glow on the horizon at nearly 10 p.m.

Having arrived relatively late on Wednesday, June 25, we figured we’d wake up bright and early the next morning since our body clocks would not yet have been reset. And we certainly expected it to be light just as early as at home (although a west-facing window was a disadvantage), so we thought the sunlight would wake us. The morning of June 26 dawned overcast, however, and the skies did not clear till midday, so it was not till Friday that we experienced a normal sunrise, though it took a while for the sun to peek over our building and fall on other structures we could see.

Back home in Fairhope, the sun was rising at 5:52 a.m. and setting at 7:58. In Portland, it was rising at 5:24 (only a little earlier) but not setting till 9:04. The daylight in Portland was actually more than an hour and a half longer than in Fairhope (15:39 hours compared to 14:06). Variations in the time of sunrise and sunset are of course affected to some extent by longitude: 15 degrees of longitude are equivalent to an hour’s difference in time; although time zone lines don’t exactly coincide with lines of longitude, Fairhope, at nearly 88 degrees west of Greenwich, is close to the 90-degree mark, while Portland, at 122.675° W, is on the other side of the 120-degree line. The difference between their offsets, a total of nearly five degrees, would make a difference of about 19 minutes.

Latitude, of course, makes a much greater difference. Everyone is familiar with the “white nights” experienced above the Arctic Circle in summer, when the sun never really sets, and our daughter and son-in-law had actually lived for a time in Norway, “Land of the Midnight Sun.” So it should not have surprised us that, so close to the summer solstice, the days were quite long, but we still found it confusing to have so little idea what time it really was and were surprised every time we looked at our watches in the late afternoon.

In discussing this with my brother from Cincinnati, who was also in Portland for my son’s wedding, we established this benchmark: I commented that Fairhope’s Fourth of July fireworks display always starts at 9 p.m., as that’s when it can be counted on to be good and dark. In Cincinnati, he said, the fireworks start about 9:45.

Following up to my previous post on sunrise and sunset, I found a page at the U.S. Naval Observatory Web site that explains this phenomenon. I don’t claim to understand it, but it does confirm what I was saying. The USNO Data Services site is also the source of other data in this and other posts. I can’t say enough good things about how useful this site is. One really cool page is the one that shows “What the Moon Looks Like Today,” and if you’re a writer and want to be sure you get your phases of the moon right, you can reference the “Phases of the Moon” page. And of course you can get sunrise/sunset or moonrise/moonset times (for a specific day or year) for any given location in the United States (or the world) from other pages at the site. The FAQ page has a wealth of other information, including links to pages at other sites.

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