This weekend (October 26th), the clocks go back in the UK, then a week later (November 2nd) they go back in the US. This causes all sorts of issues for calendar events for globally distributed teams.

Depending on who created the event, and what timezone they are in, it might or might not move back durning the gap. We’ll constantly be double-checking meeting events and making sure everyone knows. Here in Iceland, we’re on GMT year round. Today we have 8h 50m of daylight (if you ignore the cloud cover). On the solstices we have nearly 24h of sunlight or darkness, so what we call noon is pretty arbitrary.

That does mean, for our team who works with people in several timezones west of us, and several to the east, we’re in a big jumble. It’s always annoying, but we manage.

Timezones are still one of those hard problems in Computer Science. Not because it is technically complex, but because it is so tied to the strangeness of human societies. Places just decide to take part or not, or are off by 30 minutes and depending on what lat/lon you’re standing at, your clocks could be different. Keeping that database up-to-date and synced isn’t an easy task. It’s political, not logical.

The crazy part about the tz reference code and database powering so many of our devices which drive our daily lives is that it’s maintained by a group of volunteers! Proposed changes are sent to the tz mailing list and then eventually merged into a binary file which is distributed over FTP. (See RFP 6557 Procedures for Maintaining the Time Zone Database)