Track time across multiple cities with business hour indicators. Ideal for global teams.
Displaying the time in another country seems like it should be simple arithmetic: "Just take my time and add 4 hours." In reality, timezone management is widely considered by programmers to be one of the hardest problems in computer science.
It is a nightmare of politics, geography, and history that constantly changes.
To solve this, the entire internet relies on the IANA Time Zone Database (tz database). Instead of hardcoding static offsets (like "UTC-5"), systems use geographic names like America/New_York.
Why? Because America/New_York is UTC-5 in the winter, but UTC-4 in the summer due to Daylight Saving Time (DST).
Daylight Saving Time makes time non-linear. In countries that observe it, the clock suddenly jumps forward by an hour in spring (skipping an hour completely), and falls back in autumn (repeating an hour).
To make matters worse, different countries start and end DST on completely different dates. Some countries cancel it, and then reinstate it years later. The IANA database is updated constantly by a dedicated team of volunteers to track these political changes so that tools like this one display the mathematically correct time without fail.
Why do programmers use location strings like 'America/New_York' instead of just hardcoding 'UTC-5' for their code?
