I had to look up that last bit. There was a system I was working with whose developers told me “Assume Eastern Time” all the time (I'm on PDT/PST)…until the daylight saving time change in March. I missed some data from their end and their developers told me to “just fetch again and correct your code”
> While it may be safe to assume local time when communicating in the same time zone, it is ambiguous when used in communicating across different time zones.
I love how the time zone designator chapter on Wikipedia also illustrates a common complexity pitfall.
> So the zone designation for New York (on standard time) would be "−05:00"
Except for the other half of the year where it is "-04:00". If you, by chance, pick that offset up in logic, make sure that where you apply it it is still the same half of the year! Classical off by one.
> While it may be safe to assume local time when communicating in the same time zone, it is ambiguous when used in communicating across different time zones.
https://en.wikipedia.org/wiki/ISO_8601#Time_zone_designators