I feel obligated to comment on this.

Due to my work I rely on web scraped data for cybersecurity incidents. For Amazon Linux, they are disclosed with the fvcked up US datetime format (Pacific Time) and not in ISO8601 formatted strings which could imply Juliet/Local time.

In 2007 there was a new law that changed when Pacific Time enters/leaves Daylight Saving Time. Instead of making this fixed by a specific Day of a specific Month in numbered form like say "YYYY-03-01 to YYYY-10-01", they literally wrote the law quoting "first Sunday of April" to "last Sunday in October". Before 2007 it was "Second Sunday in March" to "first Sunday in November".

I'm not making this shit up, go ahead and read the law, come back and realize it's even more complex for other timezones, because some nations seem to make fun of this by going to +14:00 hours and -11:30 hours depending on the president's mood on Christmas or something.

In order to find out the Day of a specific calendar date, there's this cool article about Determination of the day of the week [1] which is quite insane on its own already. There is no failsafe algorithm to do that, each method of determining the day of the week has its own tradeoffs (and computational complexity that is implied).

Then you need to get all Sundays of a month, count the right one depending on the year, map back the date to ISO8601 and then you know whether or not this was daylight saving time they're talking about. Also make sure you use the correct local time to shift the time, because that changed too in the law (from 02:00LST to 03:00LDT and 02:00 LDT to 01:00LST before, to 02:00LST to 03:00LDT and 02:00LDT to 01:00LST after the changes).

Took me over 4 fvcking weeks to implement this in Go (due to lack of parsers), and I hate Amazon for this to this date.

PS: Write your own Datetime parser, this will help you realize how psychotic the human species is when it comes to "standards". After all this I'm in huge favor of the Moon Phase based International Fixed Calendar [2]

[1] https://en.wikipedia.org/wiki/Determination_of_the_day_of_th...

[2] https://en.wikipedia.org/wiki/International_Fixed_Calendar

Reporting of cybersecurity incidents are easily late by a month or more, time zones are well below the rounding error. You will be more accurate to display it as YYYY±6month.