[eequah9L]

An option if it gets way off would be to just express it as TZ shift. Current rate seems to be about a second every two years, so we have some hundreds of years before we need to even shift by 15 minutes. An amount of divergence that I suspect would not really be even noticeable, especially as it develops over hundreds of years. The TZ code is used widely and regularly and systems tend to know how to handle it. Leap seconds are always a bit of an adventure from what I understand. (I'm not a sysadmin, so I don't know the details.)

Like -- I don't know, but is it actually important that the solar day is tied to "wall clock day" so snugly? So what if it's a couple minutes off...?

[naniwaduni]

> Like -- I don't know, but is it actually important that the solar day is tied to "wall clock day" so snugly? So what if it's a couple minutes off...?

Even when you're assigned a correct hour-aligned time zone, you'll be off by an average of 15 minutes! Wall clock time just fundamentally has never been precise enough for leap seconds to solve a problem, by two orders of magnitude.

[brookst]

A 15 minute shift once every hundred years would wreak havoc on all of the software built when the shift was too far away to worry about.

Better to design in the requirement for all software to support these shifts, like a random 10 minute shift every day. That way nobody will write software that doesn’t support the shift.

[toast0]

Timezone aware code already has to process 15 minute timezones, IIRC; India is on a 30 minute timezone.

Some timezone changes are well published before the change and others are published after, and software has to pick up the pieces.

I'd imagine a 15 minute jump to recenter zones would be published with at least as much notice as changes to DST rules.

[hermitdev]

AFAICT from looking at the source for the tz database [0], it's capable of handling UTC offsets at least to a second level, if not fractional seconds.

[0] https://github.com/eggert/tz

[fanf2]

ISO 8601 and other display standards for timezones only support one minute resolution.