Editing Openai/69304892-a0b0-800c-94bc-95e15766d912


{{DISPLAYTITLE:Sunset time resolution issue}}

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== gpt-5-mini ==
=== User: I notice sunset time in ireland at 53 degrees latitude doesn't get any earlier than 4:09 pm around the 8th december. ===
I notice sunset time in ireland at 53 degrees latitude doesn't get any earlier than 4:09 pm around the 8th december. That's the time in tables online, and sunset time is a minute later at 4:10 by december 19th. 
Does the time actually get earlier beyond 4:09? The table only has a resolution of one minute.

=== Assistant: Ah, yes — this is a classic case of the “minute rounding” problem in sunset/sunrise tables combined with the analemma e… ===
Ah, yes — this is a classic case of the “minute rounding” problem in sunset/sunrise tables combined with the analemma effect. Let’s break it down carefully.
# Tables usually round to the nearest minute. If the table says sunset is 4:09 pm on Dec 8 and 4:10 pm on Dec 19, it might actually be 4:09:30 pm on Dec 8, 4:09:45 pm on Dec 10, etc. The true sunset time can vary by seconds, but the table only shows full minutes. So it’s very possible that the sun does start getting earlier in seconds after Dec 8, but the table doesn’t show it because it hasn’t crossed the full-minute threshold.
# The “latest sunrise / earliest sunset” phenomenon. Around early December in mid-latitudes (Ireland is ~53°N), the earliest sunset occurs before the winter solstice (around Dec 21). This happens because of the equation of time, which accounts for Earth’s axial tilt and orbital eccentricity. Sunrise continues to get later after the earliest sunset, which is why the day keeps shortening even though sunset seems “stuck” for a while.
# Seconds matter. If you look at tables or software that give sunset times in seconds, you’d see that after Dec 8, sunset might get earlier by a few seconds, then slowly reverse and start getting later again. The one-minute resolution hides this subtle trend.

✅ Conclusion: The sun doesn’t literally “stop” setting earlier. Between Dec 8 and around mid-December, the sunset is at or very close to its earliest time, but it may fluctuate by seconds. The table just rounds these changes to the nearest minute.

If you want, I can calculate the precise sunset times in seconds for each day around early December at 53°N so you can see exactly what’s happening. Do you want me to do that?

=== User: on timeanddate.com. ===
on timeanddate.com. on Dec 18th, sunset is at 4:09. It's later by a minute at 4:10 on Dec. 19th. That's before the winter solstice?

=== Assistant: Yes — that’s exactly what happens in mid-latitudes like Ireland 53°N. ===
Yes — that’s exactly what happens in mid-latitudes like Ireland (~53°N). It seems counterintuitive, but it’s a standard effect of the equation of time combined with Earth’s tilt. Here’s why:
# Earliest sunset occurs before the winter solstice. - In Ireland, the earliest sunset happens around early to mid-December, typically a couple of weeks before the solstice (Dec 21). - After that, sunset starts getting later, even though the shortest day (least daylight) hasn’t occurred yet.
# Sunrise is still getting later. - From early December to late December, sunrise is still getting later each day. - So the total day length keeps shortening until the solstice, even though sunset is already starting to creep later.
# TimeAndDate tables are accurate - If you see sunset at 4:09 pm on Dec 18 and 4:10 pm on Dec 19, that’s consistent with the earliest sunset having occurred about 10 days earlier (around Dec 8). - This is entirely normal and is a quirk of the Earth’s orbit — the asymmetry between sunrise and sunset around the solstice.

In short: sunset starts getting later before the solstice, while sunrise continues to get later, so the shortest day still occurs at the solstice.

If you want, I can make a small table of sunrise, sunset, and day length in Ireland from Dec 1–25 so you can see this pattern clearly. Do you want me to do that?

=== User: so what date is the earliest sunset? ===
so what date is the earliest sunset?

=== Assistant: For Ireland at 53°N, the earliest sunset usually occurs around December 8th or 9th. ===
For Ireland at ~53°N, the earliest sunset usually occurs around December 8th or 9th.
* After that, sunset stays roughly the same for a few days (often 4:09 pm in tables rounded to the minute), then starts getting later around mid-December.
* The winter solstice (shortest day) is around Dec 21, but by then sunset has already begun creeping later — it’s sunrise that is still getting later, so the total day length keeps decreasing until the solstice.

If you want, I can make a precise daily list of sunset times in Ireland for December to show exactly when the earliest sunset occurs and how it changes by the second. That makes it crystal clear.

=== User: but does it change by seconds, either side of Dec 8th ===
but does it change by seconds, either side of Dec 8th

=== Assistant: Yes — it absolutely does change by seconds around Dec 8th. ===
Yes — it absolutely does change by seconds around Dec 8th. The one-minute resolution in typical tables hides this, but the sun’s actual apparent motion doesn’t jump in full minutes.

Here’s roughly what happens:
* Let’s say the table shows 4:09 pm on Dec 8. That might really be 4:09:25 pm.
* On Dec 7, sunset could be 4:09:27 pm (slightly later by 2 seconds).
* On Dec 9, it could be 4:09:24 pm (slightly earlier by 1 second).

So around Dec 8, sunset is at its earliest point, but the change is very small — just seconds per day. This is why the table rounds multiple days to the same “4:09 pm.”

✅ In other words:
* Dec 8 is approximately the earliest sunset.
* Sunset does fluctuate by seconds day-to-day around this point.
* After a few days, it starts to get later in minutes again (e.g., 4:10 pm on Dec 19).

If you like, I can generate a second-level sunset table for early December in Ireland so you can see the tiny second-by-second changes. Do you want me to do that?

== References ==
<references />


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