My friend had her baby Thursday. But I was thinking, what if she’d given birth tonight at 2 a.m.? Would it be recorded at 2 or 3 because of the time change? 
There is no 2am tomorrow, but there will be two one early morning this Fall.
Yeah, the instant that would otherwise be 2:00 a.m. will actually be 3:00 a.m.
If twins are born, one at 2:45 before a time change and the other at 2:15 after the time change, is the second-born legally the older of the two?
Similarly, I have crossed the Intl Date Line three times going west, but only once doing east. According to the Phileas Fogg calendar, that makes me two days older than I thought. Do I need to change my birthday?
In the spring time change, there is no 2:00. The minute after 1:59 becomes 3:00, so one twin will be born at 3:15 and the second one at 3:45.
In the fall time change, the minute after 1:59 becomes 1:00 all over again. An hour later, 2:00 comes as it normally does, so one twin will be born at 2:15 and the second at 2:45, just as in a normal day. The twin born first will be recorded as the older of the two.
Keep system time. Count the number of seconds elapsed since the start of the Unix epoch at 1 January 1970 00:00:00 UT and you won’t worry about arbitrary DST artifacts. Translate that to the Discordian calendar for purity.
a related question: how does the extra hour count for people on shift work?
Some jobs have strict rules about how many hours you are allowed to work, for safety reasons.
Long-haul truck drivers are (I think!) absolutely required to stop driving after x number of hours on the road. How do they account for the time change?
Just make sure you use more than 32 bits.
I stand corrected on the nitpick.
Please change my question to:
If twins are born, one at 1:45 before a time change and the other at 1:15 after the time change, is the second-born legally the older of the two?
Just do your best to not have anything interesting happen in your life during the two hours between 1am and 2am on the “fall back” Sunday in late October. 
AFAIK, they’re legally the same age.
If the time was important, it would be incumbent on the doctor to record the time standard s/he was following, which would establish it definitively. Or the lack of it would establish that the records were ambiguous.
The doctor could record the times in GMT, which remains the same regardless of Daylight Saving Time.
A related question; when is the time of birth? When the top of the head emerges? When the feet emerge? It’s not an instantaneous event.
The run tracking software we used at the ambulance had an edit to ensure that all times for each sequential event were later than the last time (Dispatch --> Enroute --> Arrive --> etc.) but it didn’t account for the end of DSL. This forced us to ‘lie’ on a few Fall calls over the years as we could, say transport a patient before we were ever dispatched. I wonder what would have happened if one of those calls was ever involved in a lawsuit & how an ambulance-chaser might use that ‘inconsistency’ to pick apart the rest of trip sheet which documented care & treatment.
Britain has BST, British Summer Time. When it’s used as a universal time, it’s usually called Zulu Time or UTC, or Coordinated Universal Time. Checking that out to make sure I was right, apparently some countries do call it GMT because it’s based on GMT, but I think that has the potential to cause confusion, since GMT isn’t actually used year-round.
It would be a good way of recording the time, but don’t doctors usually have to record the time according to local time? They can’t just record it as if it happened in a different time zone. It would be a cool starting point for a short story, actually - twins born, the eldest inherits something important, like a kingdom, and there’s debate over which actually counts as older.
I’d assume it’d be relatively rare because twins are more likely to be born via elective c-section (about 75% in the US and 60% in the UK), so that can be planned, and probably won’t take place in the middle of the night. But apparently it has actually happened that twins have been born with the older one being the younger. And another.
So if even twin births are recorded using daylight savings, then presumably singleton births are too.
Actually yeah, for the US at least there’s a factual answer. https://www.cdc.gov/nchs/data/misc/hb_birth.pdf Local time is used, including daylight savings time.
Turns out there is a factual answer, for the US at least. https://www.cdc.gov/nchs/data/misc/hb_birth.pdf Local time is used, including daylight savings time.
Another nit picked: It’s daylight saving time not daylight savings time.
DST doesn’t cease to exist in the fall. It ceases being used. If the time falls back an hour, and that causes your sequence of events to look funny, there’s nothing stopping you from recording it in DST throughout, or using standard time early.
To the trucker/shift worker questions…are you serious? You pay the guy who worked 9 hours for 9 hours of work. The trucker has to stop after x hours of driving, regardless of what the clock says. 1:15 EST happens after 1:30 EDT, just like time zones. No trucker has to continue driving past his or her allowed hours because they drove west. It’s not hard to annotate, calculate, or conceptualize.
On Saturday night at 11:58 PM, about two hours before the clock change, I set the alarm clock in my phone to wake me at 6 AM. When I pressed Save, it sent the message: “Alarm set for 5 hours and 2 minutes from now.”
I was SO surprised and impressed that it figured out the math correctly. Among all these modern gadgets, cell phones are sort of famous for adjusting themselves when we go on or off daylight time. But I always presumed that this only referred to the adjustment itself. I never realized that this would be correct too. I imagine that in the internals of the phone, there is no real 24-hour clock that needs to be adjusted, and it stores all times on some sort of Julian Calendar system or something like that, and converts to human-readable only when it needs to.
Maybe we should tell OSHA about DST? Who wants to do it?