Why is sunlight in mornings and evenings more intense in the temperate zones than in the tropics? It is more difficult to drive facing the sun at 7am for example in Auckland, NZ than at Singapore.

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    I'm voting to close this question as off-topic because it is about driving in general? – njzk2 Feb 16 '17 at 22:03
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    @njzk2 This is not about driving but it is about astronomy. But I don't think it can be moved after it has and up voted answer. astronomy.stackexchange.com – paparazzo Feb 16 '17 at 23:37
  • I was thinking this is more about Earth Science than Astronomy, given it is about how solar intensity at sun set/rise differs across latitudes on Earth. – cr0 Feb 17 '17 at 13:40
  • Sorry I didn't notice this until after my answer was posted, but I may have read your question backwards. Are you suggesting that the sunlight could be less intense at the equator at 7am and more intense closer to the poles at that time? – Loduwijk Sep 28 '17 at 19:50

Part of it is the distance from the sun to the horizon. In the tropics the sun path angle is nearly at right angles to the surface. Sunsets are short. The time between 10 degress above the horizon and below the horizon is also short.

As latitude increases, the angle of the sun's path decreases. The time to cross that last 10 degrees above the horizon increases.

At mid latitudes (40-50) in the winter the sun never gets far from the horizon. In Edmonton (54 N) I have to use my sunvisor at noon driving south.

Mid latitudes in summer however here, have sunrise at Too Damn Early, and sunset at After My Bedtime, and so the times we are driving about, the sun is high in the sky.

Also: Near the equator, day length doesn't vary much. If you have a pattern of commuting at 7 a.m. then possibly in Singapore that doesn't correspond to a time when the sun is a nuisance, and it remains not a nuisance all year. Where in New Zealand, you are going to facing the glare at some point in the year, and that's what you remember.


You need to include winter to summer but based on your latitude the sunlight has to pass through a different distance of the atmosphere at dawn and dusk.

Maybe this is what Botsford is saying.

Circumfrance of earth at the equator is about 25,000 miles.

When the sun passes over the equator the circumference at 45 degree towards the sun is about .7 that of the equator. So the sun has .7 the atmosphere to pass through and get filtered. 45 degrees is like Chicago.

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