Dawn, dusk, sunrise, sunset and twilight

Dawn occurs before sunrise, before the top of the Sun reaches the horizon. Astronomical Dawn is the point at which it becomes possible to detect light in the sky, when the sun is 18° below the horizon. Nautical Dawn occurs at 12° below the horizon, when it becomes possible to see the horizon properly and distinguish some objects. Civil Dawn occurs when the sun is 6° below the horizon and there is enough light for activities to take place without artificial lighting.

Dusk occurs after sunset, once the top of the Sun has passed the horizon. As with dawn there is astronomical dusk, nautical dusk and civil dusk, occurring at 18°, 12° and 6° below the horizon respectively.

Twilight is the name given to the period between dawn and sunrise, or between sunset and dusk, when light is still visible in the sky due to sunlight scattering off the atmosphere. It can also be separated in astronomical, nautical and civil sections by how far below the horizon the Sun is.


Sunrise and sunset are the points at which the top edge of the Sun reaches the horizon; the only difference between them is the direction in which the Sun is moving at the time. It actually occurs when the top of the Sun is 0.57° below the horizon due to refraction of the Sun’s light by the atmosphere.

50 thoughts on “Dawn, dusk, sunrise, sunset and twilight

  1. During Civil twilight it is bright enough to carry out normal activities
    During Nautical twiligh there is enough light to distinguish the horizon for navigational purposes
    Durin Astronomical twilight there is too much light in the sky to perform astronomy

  2. Thank you for this explanation. A small debate in my household ensued as to when I could/should eat as one who indicated she was going to fast from periods of dawn to dusk. My partner believed that sunrise and sunset were synonymous with dawn and dusk. Your visual aid was particularly helpful in our discussion.

  3. This was helpful. As I was gazing at the weather it showed when dawn was and when sunrise was, as well as dusk and sunset. They were all at different times, so I didn’t understand. I thought sunrise=dawn and sunset=dusk. This explanation was very helpful.

  4. Thank you.
    A request: what are the definitions of ‘evening’? After sunset; late afternoon; even afternoon from 12 pm?

  5. There is no set definition for evening. I think most people would say from 1700-1800 onwards, but it has nothing to do with the Sun, Moon, etc.

  6. God, it took me forever to find out whether twilight was BEFORE or AFTER sunset. That should be a pretty easy answer, but everyone was just telling me the angle of the sun, as if I can look outside and have any bloody frame of reference for the angle of celestial objects. “Oh, yeah, it’s at 17 degrees right now.”

  7. In general, how long do each of those periods of twilight last? (If it varies by day, say, on the solstice)? About how many minutes is six degrees? Thanks! This was really helpful for an art project I’m working on this summer.

  8. Oh. Of course. That makes sense. Thanks!! If you’ll entertain one followup question: How long would 6 degrees (or a total of 18 degrees for the 3 parts of twilight) last at latitude 36.531364 (northern Tennessee). If this is more than you signed up for, I’ll certainly understand. Thanks!

  9. Why does the duration of dawn, at a given location, vary through the year?

  10. RFox, it’s because the Earth is tilted. This means that it isn’t always the same “face” that is pointed towards the Sun. Same reason for the change in the seasons.

  11. Would it be correct to say “as the sun begins to dawn” or must you say “as the sun begins to rise”? Thanks

  12. According to the Bible Matthew 28:1- that would be at dusk or at dawn; that a day begins?

  13. Generally, the explanation is very good and useful. But…
    Dawn and dusk are not just moments, not points of time.
    Dawn is period(!) of twilight before sunrise, and dusk is period(!) of twilight after sunset.
    Twilight is a general definition of state of absence of direct sunlight.

  14. Thanks a lot for this piece of information…It dawned to me that I read this article exactly 5 years after it was written!!!!!!?

  15. ‘DM’..? Rlly.. bbl qstn t scntst? Y gt t nw th, rght?…MrRd hsn’t cght p t Gd yt..ftr ll..h’s nt NSTN!!

  16. Kathy M.
    The gloaming of the day refers to dusk. As the sun set the gloaming (glowing) of the sky awoken the nightlife.

  17. I hope you are still open for answering questions… For this week-end day July 21/22 does this make sense?

    8:19 is ‘sundown’ then nightfall follows at 9:05pm .


  18. I guess I wasn’t specific enough…
    IS there a determining factor that decides the exact hour to the minute of evening, dusk, sunset, nightfall, or dusk? I have a specific reason to learn of this info. Thank you.

  19. Yes, there is. Did you actually read the post? It’s to do with how far (as an angle) below the horizon the Sun is. Sunset and the various dusks depend on that. “Nightfall” is not a thing, it doesn’t have a specific meaning.

  20. Laurie, most weather apps will tell you the times for dawn, sunrise, sunset, and dusk for your current location and any other location you choose. Hope that helps.

  21. ““Dawn” is not a verb”.

    In the phrase “the awful truth was beginning to dawn on him” dawn is clearly a verb. It is also a verb when you speak of a day ‘dawning’.

    ““Sundown” is not a thing, and the times will depend on your location”.

    Sundown is the american term for sunset. Perhaps the poster is American?

    ““Nightfall” is not a thing, it doesn’t have a specific meaning”.

    It may not have a specific technical meaning, but it clearly is a ‘thing’.

Leave a Reply