Sunrise, Sunset

northern exposures

This fellow won’t be getting out to play for awhile, but most of his friends are under the weather, too. See the nearest set of tracks crossing right to left? Snowshoe rabbits.

What is your length of day, today? Today is three minutes shorter in Dallas than it is in Fort Yukon. In a practical sense, our days have been longer for some time. It all depends on how you measure daylight, and believe it or not, there is more than one way to do that.

There is sunrise and sunset, measured at the moment the sun drops below the horizon. Meteorologists refer to the time between sunrise and sunset as the “length of day.”

Too easy? Don’t be disappointed, there is always civil twilight to complicate your day. Civil twilight is defined as “the time period when the sun is no more than 6 degrees below the horizon at either sunrise or sunset. The horizon should be clearly defined and the brightest stars should be visible under good atmospheric conditions (i.e. no moonlight, or other lights). One still should be able to carry on ordinary outdoor activities.” See how easy it is to complicate things? Scientists refer to the time between civil sunrise and civil sunset as the “length of visible light.”

Still too easy? There’s always nautical twilight, “the time period when the sun is between 6 and 12 degrees below the horizon at either sunrise or sunset. The horizon is not defined and the outline of objects might be visible without artificial light. Ordinary outdoor activities are not possible at this time without extra illumination.”

And for the really hard to please, there is always astronomical twilight, “the time period when the sun is between 12 and 18 degrees below the horizon at either sunrise or sunset. The sun does not contribute to the illumination of the sky before this time in the morning, or after this time in the evening. In the beginning of morning astronomical twilight and at the end of astronomical twilight in the evening, sky illumination is very faint, and might be undetectable.”

So how do I measure the length of a day? I look out the window. If I see light in the sky, then it’s day. I like simple.

Here is how today stacks up in Fort Yukon and around the world:


length of day

civil light

nautical light

astronomical light

Fort Yukon 12 h  7 m 13 h  51 m 16 h  0 m 18 h  30 m
Dallas 12 h  4 m 12 h  54 m 13 h  52 m 14 h  49 m
Copenhagen 12 h  3 m 13 h  17 m 14 h  45 m 16 h  16 m
Istanbul 12 h  3 m 12 h  58 m 14 h  3 m 15 h  7 m
Christchurch NZ 12 h  15 m 13 h  12 m 14 h  20 m 15 h  29 m

How does your city stack up?

All definitions and times based on information found at WeatherUnderground.


10 thoughts on “Sunrise, Sunset

  1. You found Denmark for me :D. I also just look out the window, today it’s all raining so the daylight it’s replaced by bulb light sometimes,haha.

    1. I hope you like the rain. Years ago I always enjoyed resting in the daytime as rain pattered on my rooftop, but here we have so little. Here, it is dry dry dry. I saw a little drizzle last August. Before that, October or November of 2010 must have been the last time I saw rain. I do miss it very much.

  2. This was insteresting for me, I haven’t interested before with these details… You are amazing Thank you dear Dave, I will try to read more and to learn what means all these details… With my love, nia

  3. I think astronomical twilight must be when you can first detect a faint lightening of the sky, and the last moment you can detect any light at all in the evening. Those are the two moments that mark the beginning and ending of a day for me.

    Here is an interesting way to think about all those numbers. They show that you and I have almost exactly the same length of day between niasunrise and niasunset (haha), but my twilight is three hours longer than yours. So my day seems to stretch on longer than yours does.

    I can’t believe you find the time to visit with me everyday. Thank you, Nia, I enjoy our chats.

    1. Sunrise and Sunset times are great… They always hit me… Someone told me once upon a time, the sun doesn’t go down, we try to catch the sun… In my youth ages, to be honest I didn’t interest with the light so much… When you get older, when your eyes can’t see as before, when you notice that you need always more light… It hits. There is a film dear Dave, maybe you know this film, by tyhe director that was one of my favorite names, Akira Kurosawa’s film, “Dersu Uzala”…

      In this film the man impressed me so much. He is living in the mountains… For him, the sun is a man. And he always talks about sun as a man and he says that without Sun nothing could be in this life… On the other hand, another impressive point for me, the sunset and sunrise times are not same… They are all different in different places… of course geographically this is so normal but impressive for me again… Just for this I wished to make a great poject, Travel the sunset and sunrise times in the world… About my time… in these days I am at home and at my desk… so I can find time to write and to read… Actually this is my life dear Dave, without writing and reading I can’t imagine myself… On the hand I am happy in this peaceful place with beautiful and creative people… But normally I try to visit all my beautiful blogger friends’ blogs too… Another note too, my letter is on the way of Alaska, as I checked today, it arrived to Germany… then they will carry it to Anchorage… then will be in your address… I hope.

      You are welcome and Thank you, have a nice day, with my love, nia

    1. Tania, I really do appreciate your kind words, but I must decline the award. I hope you and everybody that visit me will keep coming back, as you are all like friends to me. Congratulations on your most recent award!

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