Observations

The daily motion of the Sun throughout the year as seen from the southern hemisphere

Motion Sun solstices equinoxes diagram by Nick Lomb

An animated diagram showing the daily motion of the Sun at the turning points of the year, the summer and winter solstices and the spring and autumn equinoxes, as seen from southern latitudes at places such as Sydney, Melbourne or Perth. Diagram Nick Lomb

Jim asked:

Would like to ask a question regarding the direction of Sun rise and set during Summer here in Perth. W.A.

I have been taking compass bearings of the direction the Sun has been rising and setting during Dec here in Perth.

I have found that the Sun is rising in the South East and sets in the South West.

I would have expected that the Sun would rise in the North East and set in the North West. Obviously my reasoning is flawed and I was hoping you could explain why.

My reasoning is that the furthest South the Sun gets is 23.5 degrees latitude on the Summer Solstice (22 Dec 13). As Perth’s latitude is nearly 32 degrees it would mean that the Sun is to the North of Perth and because of this I would have expected that the sun would rise to the North of East and set to the North of West.

Thanks for considering this question.

Regards

Jim

Answer:

As can be seen in the diagram above, during each day the Sun moves in an arc that is always tilted at 32° (Perth’s latitude) to the vertical and with the highest point towards the north.

At the March (autumn) and September (spring) equinoxes the Sun rises in the east, moves toward the north and sets in the west. These are the only times in the year that the Sun rises due east and sets due west. At the highest point of the daily arc at the equinoxes the Sun is 32° (Perth’s latitude) to the north of the zenith, the point overhead.

At the June (winter) solstice the Sun rises north of east, makes a small circle towards the north and sets north of west. At the highest point of its daily arc the Sun is 55.5° (32° + 23.5° (the tilt of the Earth’s axis)) to the north of the zenith.

At the December (summer) solstice it rises south of east, makes a large circle and sets south of west. At the highest point of its daily arc the Sun is 8.5° (32° – 23.5°) to the north of the zenith.

The above calculation makes the significance of the Tropic of Capricorn obvious. At a southern latitude of 23.5° at the summer solstice the Sun is overhead. In Australia the Tropic of Capricorn passes just to the south of the city of Rockhampton.

Sunset over Balmain as seen from Sydney Observatory on 29 August 2005 photographed by Nick Lomb

The Sun setting over Balmain, as seen from Sydney Observatory, on 29 August 2005. Over the next few weeks sunset moved to the left or south and by 23 September, spring equinox, it set behind the tower near the left hand edge of the picture. Photo Nick Lomb

The yearly back and forth movement of the rising and setting Sun along the eastern and western horizons, respectively, provides a useful calendar of sorts. When the Sun sets furthest to the north it is winter, when it sets due west it is spring or autumn and when it sets at its furthest to the south it is summer.

I hope that this diagram and text have helped to clarify the daily motion of the Sun at the different seasons of the year.

79 responses to “The daily motion of the Sun throughout the year as seen from the southern hemisphere

  • The original question is a good one but the answer is the standard answer that does not take into account something unusual was observed. The earths tilt has increased. Meaning the sunset is further south than its ever been. The sun should never be further south than the tropic of Capricorn, but it is. How is this not affecting GPS? It is but software corrects the changes. How is it not affecting star sightings? They are far away and the changes are minimal anything else can be adjusted as its is all digital. Why hide the change in Axial tilt? This is largely the kaey factor in the wild weather and will melt the poles.

    • Jamie, nothing unusual was observed by Jim, just his reasoning was flawed as he says. The Earth’s tilt is changing but only by a couple of degrees over about 40,000-years. The Tropic of Capricorn is a line defining where the Sun is directly overhead at the December solstice, it doesn’t define where the Sun rises or sets.

      • This phenomenon has bugged me for years too. As a farmer who is observing the outdoors every day, and who is constantly using gps technology for auto steering machinery, my instincts are that the sun is rising and setting way further south (- easily 20 degrees) of east and west. We are at a latitude of 33.5 in WA. At midday early January the sun is only a degree Nth of vertical. The schematic by Nick helps diagrammatically but my perception of drift would be that the earth is tilting more. Surely this must have season climate effects.

        • Steve, but your instincts and perception are not good enough. You’ve got to measure things! That’s science. If the Earth’s tilt, or obliquity, were changing at a rate detectable by eye then no telescope on Earth would correctly track the stars, thousands of astronomers would have to update their star charts and software, and the ‘midnight sun’ would appear further from the poles. None of this is happening. And yes, at a latitude of 33.5-degrees south (almost the same as Sydney Observatory) on the summer solstice (Dec 22 in 2018) the Sun rose 29-degrees south of due east and it set 29-degrees south of due west.

          • Strewth , nearly 30 degrees. That’s a lot of southern sun hours in December January. It certainly has had me concerned, but now with your help, I shall be no more. Thankyou guys.

  • Hi, I see that the sun is at its lowest on the 21st of June at the beginning of winter and at its highest at December 21st (?) Can you advise for how long it remains in these positions and when it begins to move, say from its lowest point on the 21st June. ie where will it be say on the 21st of July? Does it remain at its lowest point for just the one day?

    • Alex, The Earth is continuously moving around the Sun, which in combination with Earth’s axial tilt leads to the apparent change in maximum height (above the horizon) of the Sun in its daily arc and the lowest & highest points you mention. The continuous movement means that, from a particular location, the Sun is at the lowest point in its daily arc on only one day of the year – the June solstice. The day after (or before) winter solstice it will be a little higher. While measurable, this would not be noticeable to a casual observer without instruments. It might take a month or more before it becomes readily apparent to the eye.

  • Like Jim (who asked the question) I have been wondering about the direction of the sunrise and sunset. This info-graphic answers the question perfectly, thank you.

    • Jon, Really? That would be a very hot location! I’m sure you are wrong, given that the Earth is spinning in space and revolving around the Sun at a distance of about 150,000,000-km. Perhaps you would like to present your evidence.

  • Nick! I just wanted to say this is exactly the animated graphic I was looking for to show someone the particular point I was trying to make. So great to find it. Thank you.

  • in Brisbane, Australia would an apartment on the north side get more winter sun that one on the south side? I think the answer is yes, but I’m not sure.

    • Derek, Given Brisbane is south of the Tropic of Capricorn, then yes you are correct, an apartment on the north side does get more winter sun that one on the south side. In fact the south facing walls/windows of the south side apartment wont get any Sun in winter.

  • Hello i’m tying to figure out where exactly the sun will set (in degrees) from Farmingdale New York 40° 43′ 57″ N  73° 26′ 43″ W. Specifically from November 20th to December 4th even if you could just tell where it will set on one of those days and how many degrees it will move per day during this time. I’ve been trying to figure out this information for a school project but I’m having issues finding this information. Thank you for your help. – Greg Verrelli

  • Hi There,

    Please suggest which direction Sydney is located from the Perth, WA?

    I am quite confused.
    Please advise.

    Thanks.

  • Hi,
    Someone told me that at midday, if you’re in the northern hemisphere then the sun is in the south. Therefore, if the sun is burning your eyebrows, you’re going north, if it’s burning the back of your head, you’re going south. Is this true? I can’t seem to figure it out!
    Thanks!

    • Heather, Have another think about what you’ve said there. Particularly about where the Sun is at midday and how that relates to your ‘burning eyebrows’ and the direction you must beheading in.

    • I’m from the Northern Hemisphere. The sun is in the south, but if the sun is burning your eyebrows, you’re going south since you’re facing the sun. If it’s burning the back of your head, you’re going north, since you’re facing away from the sun.

      • I think that depends a bit. When you are north or south of the Tropics, things are pretty clear cut, the sun is always to the south or north respectively. But in between the two Tropic lines, it depends on the season and time of day!

  • Question, does the sun always rise due east and set due west on the equator? Dont forget, you always have a 12 hour day and a 12 hour night there. I live in cleveland ohio USA. Latitude 41 degrees north, 82 degrees west. It is now the first day of summer, 6-21-27. Ed.
    Make that date 6-21-17. Got 10 years ahead there. Sorry. Ed.

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