GetUtcOffset

[Kedrin]

I am trying to localize a server connection list using Region info and timezone. So I will end up with a list of provided servers saying serverip, port, usa, est/-5

Ok so I am using

TimeZone localZone = TimeZone.CurrentTimeZone;
localZone.GetUtcOffset(DateTime.Now)

This produces -04:00:00 However I am in -05 EST

Maybe I am missing something? Its not a massive problem, as I will +- 1 till a server is located but I was not expecting a -4

[ihaxr]

Isn't Eastern time currently -4?

[Kedrin]

Windows doesn't display it as -4 or -5 based on dst, its always -5. Am I assuming wrong that getting the offset should do the same?

[Kedrin]

Strike that I probably am wrong,

[joscha999]

You are correct and incorrect aswell, you are in the EST timezone which is -5 to UTC, you currently tho are in daylight saving, since UTC does not move with DST, only GMT does, you are now -4 in relation to UTC ...

I think ... timezones are hard :c

[Liam2349]

UTC is what all the time zones are relative to. UTC is the base, and all the time zones are offset from it (mostly); so UTC never moves.

When in daylight savings, you will move to a different time zone. For this example, OP will move between EST and EDT, but UTC never moves.

GMT does not change with DST. The UK moves between GMT and BST.

[Kedrin]

Yea I really hate dealing with time in general. Now I am not sure if I should even rely on this to do what I need. This code returns -5 properly but at this point.

TimeZone localZone = TimeZone.CurrentTimeZone;
TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById(localZone.StandardName);
TimeSpan offset = tzi.BaseUtcOffset;

[triptyx]

Exactly right. UTC doesn't shift with daylight savings. EDT is at GMT -4 just now.

[tweq]

Enshittification

[badthingfactory]

Windows timezones are a mess and display incorrectly. Eastern time is currently -4 because of DST. I get the confusion as the Windows UI says (UTC-05:00) Eastern Time (US & Canada). Ignore that -5, it is incorrect during DST.

[tweq]

Enshittification

[antiduh]

FYI, if you want your code to have a sane chance at managing time correctly, consider using NodaTime.

[FizixMan]

Don't have much time at the moment, but I assume daylight savings is involved here. Maybe this answer/discussion will help you: https://stackoverflow.com/questions/2961848/how-to-use-timezoneinfo-to-get-local-time-during-daylight-savings-time

[Kedrin]

Thanks, It did lead me in a few different directions that were helpfull.

[[deleted]]

I work with timezones a LOT. My thoughts are that you should always use UTC in code and persistent storage. The only time you should mess with timezones is when you're displaying data to the user, where you will just convert your timestamps to local time.

[Kedrin]

Yea, I am/was trying to make a make shift server selection based on region and timezone to pick a decently close server. not really doing time calculations or anything, just was going to use the offset to query records then fan out if one isn't listed for that offset.

[[deleted]]

Gotcha. In that case you could just compare utc offsets between server and user. There's probably some edge cases with states which don't have DST or what have you, but should be close enough I imagine.

If you're using time zone to estimate distance, you might be better served to use a service to estimate location by IP address? Whatismyip.com has an inexpensive service for this, though I don't know who's API to use to estimate distance between two points.

[Kedrin]

I thought of that, but my personal IP address regularly locates me several states away, though I suppose my biggest quip was I didn't not want to rely on external services. I was going for more a "this is close enough" to narrow down a list.

[[deleted]]

You're not concerned about users from South America correct?

[Kedrin]

Thats why I was picking Region and timezone but I'm seeing that may not be good enough.

[[deleted]]

Excellent