Re: Which affects sunrise/sunset times more, latitude or time zone location?

Hello!

You may easily both be right depending on 1) the particular time zone Town A and B are in and 2) the difference in latitude between Town A and C. The answer to your question varies based on case 1 because time zones are set up arbitrarily. As you can see by following this link, some time zones, such as the one for China labeled "H", are extended to incorporate territorial boundaries. Therefore, someone living at the same longitude in India as someone at the same longitude in China will have a three-hour time difference! So in that case, the difference between sunrises and sunsets could be very different from a town on the eastern side of the time zone and a town on the western side.

However, your husband also raises a good point with latitude making a significant difference in sunrise and sunset times. Furthermore, his answer will vary depending on the time of year.

Let's use Iceland and Morocco as an example. Neskaupstadur (Nordfjordur) in Iceland has latitude of 65° 09' N and a longitude of 13° 41' W. Casablanca in Morocco has latitude 33° 35' N and longitude 7° 39' W. Both countries are in the same time zone and have similar longitudes (they differ by ~7 degrees), but differ in latitude by ~32 degrees. Using this sunrise/sunset calculator and the coordinates above, we find the difference in sunrise for these two locations differs by 3 hours and 17 minutes for December 4, 2002. But that's what about in summer time when the days are even longer? Using the same sunrise/sunset calculator, we find that the difference in sunrise for the two locations differs 3 hours and 32 minutes. Either way, this difference is longer than the difference for many of the smaller (skinnier) timezones.

I suggest you play around with the sunrise/sunset calculator with specific latitudes and longitudes of interest to finally settle this argument.

Good luck!

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