# What time and where on earth is the latest solar noon?

For context: I am visiting Portugal from Australia and after observing that people tend to start their days later, I realised that solar noon also seems to occur at a later time - about 1.20pm at the moment. I don't recall solar noon every occurring at such a late time in Australia. When and where is the latest solar noon on earth?

• This really is more about local definitions of time relative to Zulu than about anything astronomical. – Carl Witthoft Oct 17 '16 at 12:16

That should be in western China, since all of China uses Beijing's time zone.

--- Edit below ---

In response to the comment by @adrianmcmenamin: I'll leave this as guesswork since I simply don't know the peculiarities of every timezone there is. Here's a back-of-the-envelope calculation for local noon in western China.

The Sun covers 15 degrees in a period of 1 hour. All of China is on Beijing time (UTC + 8 hours). With the above, it's centred on $15 \cdot 8 = 120^{\circ}$ east. As a consistency check, Beijing is at $116^{\circ}$ east. The westernmost part of China is at about $73^\circ$ east (See here). Local noon there is delayed by $(120^\circ - 73^\circ)/(15^\circ/h) \simeq 3h$.

So, local noon is a little later than 3pm. This is discounting daylight savings time, which is not currently observed in China.

• Please don't make guesses by way of answers. This would have been better as a comment. – adrianmcmenamin Oct 15 '16 at 22:08
• Kashgar, China, which is just about the westernmost town in China, experiences solar noon around the beginning of February at about 3:10 PM, so I guess my answer of Adak, Alaska doesn't quite make it. – BillDOe Oct 17 '16 at 17:30

I believe that honor may belong to Adak, Alaska where solar noon does not occur during DST until 2:52 PM, or 1:52 Standard Time. All of Alaska is on Juneau time. You can check it here.

Edit:There are maps here that show the offset between local and solar time. It's pretty informative. There may be other areas besides western China where solar noon is very late (maybe I'll modify a spreadsheet and see if I can some up with something).

• Please see my comment to the answer provided by @Alex. Western China seems to be the correct answer. – BillDOe Oct 17 '16 at 17:31
• We'll both be wrong if someone in the central Pacific decides to move their country to the other side of the international dateline - noon will be 24 hours off :-) Great map in the link, btw. – Alex Oct 18 '16 at 18:59

It's probably a neighbourhood of the South Pole. You use New Zealand time there, but the laitude varies from 0 to 360 degrees, so the solar noon is at midnight at some places. And also in some regions of northern Antarctica there are deviations in solar noon up to 7 hours, because time zones are very large there. But if you want some inhabited civil settlement, it's St George, USA, Aleut islands - solar noon happens there around 15:02 - 15:27 in warm period, and also this is the farthest from poles inhabited place (and probably any land) with midnight sun - from 5 Jul to 14 Jul the Sun sets there around midnight and rises around 6:30 am, even though it's on the same latitude with Riga and Edinburgh. In Jigenxiang, the westernmost settlement in China, solar noon is on 15:17 in February. Then, theoretically, in westernmost point of China, solar noon is around 15:19 in February. **Actually Attu, Canada has 15:37 solar noon on 10-11 March (but St George still has farthest from poles polar day - in Attu latest sunset is at 23:56)

It was Kashgar in China back in 1991 when there was DST. Noon occured at 4:10 pm and sunrise and 8:30 am and sunset at 11:45 pm. Civil twilight continued even after midnight.