"Let's meet at 3pm my time" has derailed more international calls than almost any other sentence in remote work. It assumes the other person knows exactly which time zone "my time" refers to, whether it's currently observing daylight saving, and which side of midnight the meeting actually falls on. Time zones aren't hard, exactly — they're just full of small, quiet exceptions that break assumptions people don't realize they're making.
How Time Zones Work
The Earth is divided into 24 primary time zones, each approximately 15° of longitude wide (360° ÷ 24 hours = 15°/hour). In practice, though, political and geographic factors mean real time zones rarely follow neat lines on a map — countries choose zones for economic or administrative convenience as much as geography. China uses a single time zone (UTC+8) despite spanning roughly five geographic zones' worth of longitude. India uses UTC+5:30, a half-hour offset rather than a full hour. Nepal goes further still, using UTC+5:45.
UTC: The Universal Reference
UTC (Coordinated Universal Time) is the global time standard against which every other time zone is expressed as an offset. New York (ET) is UTC-5 in winter, UTC-4 in summer. London (GMT) is UTC+0 in winter, UTC+1 in summer. Tokyo (JST) stays at UTC+9 year-round. Dubai (GST) is UTC+4, also year-round. When a time is expressed as "14:00 UTC," anyone anywhere can convert it to their own local time independently using their offset — that's the entire point of having a single reference point. UTC itself never observes daylight saving time.
| City | Time Zone | UTC Offset (Winter) |
|---|---|---|
| New York | EST | UTC-5 |
| Chicago | CST | UTC-6 |
| Los Angeles | PST | UTC-8 |
| London | GMT | UTC+0 |
| Paris/Berlin | CET | UTC+1 |
| Dubai | GST | UTC+4 |
| Singapore/HK | SGT/HKT | UTC+8 |
| Tokyo | JST | UTC+9 |
| Sydney | AEST | UTC+10 |
Daylight Saving Time Complications
Most of the US, Canada, and Europe observe Daylight Saving Time (DST), advancing clocks by 1 hour in spring ("spring forward") and reverting in fall ("fall back"). US DST in 2026: clocks moved forward on March 8 and back on November 1. DST isn't universal — Arizona (except the Navajo Nation), Hawaii, and most of the world don't observe it at all. This means the UTC offset for DST-observing regions changes twice a year: New York sits at UTC-5 in winter but UTC-4 in summer. Always verify the current offset when scheduling an international meeting rather than assuming last month's math still holds.
💡 DST creates real scheduling gaps because different countries change their clocks on different dates — the US and UK, for instance, don't always flip DST in the same week. A New York–London meeting locked in at "3pm London / 10am New York" needs to be rechecked every March and November, because for a week or two, only one side of the call may have actually changed its clocks yet.
Scheduling Global Meetings
Best practices for multi-timezone scheduling: share meeting times in multiple time zones explicitly — "Tuesday 2pm ET / 7pm GMT / Wednesday 3am AEST" — rather than leaving anyone to do the math. Use scheduling tools like World Time Buddy or Calendly that display all participants' local times side by side. For recurring meetings, rotate any inconvenient time slot fairly across locations rather than permanently burdening one office. Send calendar invitations with an explicit time zone attached — most calendar apps then convert automatically to each recipient's local display. For 3+ time zones, look for the overlap window where everyone falls within reasonable working hours rather than picking a time that's only convenient for the organizer.
Essential Time Zone Tips
- When in doubt, use UTC — it's unambiguous and universally understood by anyone technical
- Verify DST status before important international calls — offsets shift twice yearly, and not on the same dates everywhere
- Use world clock widgets — iPhone, Android, and Windows all support multi-city clock displays natively
- Account for date changes — a 9pm Monday New York call lands at 10am Tuesday in Tokyo
- Use IANA timezone names (America/New_York, Europe/London) instead of abbreviations wherever precision matters — EST and IST are genuinely ambiguous, since IST alone refers to Indian Standard Time, Irish Standard Time, and Israel Standard Time depending on context
Quick Checklist
- Always specify time zone explicitly when sharing meeting times — "EST", "PST", etc. are ambiguous (EDT vs EST differs by season)
- Use UTC for technical scheduling and logs — it never changes for DST
- Check DST status when scheduling international meetings in March and November
- When scheduling across 3+ time zones, use World Time Buddy to visualize working hour overlap
- Always include the date when crossing midnight — a 9pm ET meeting is next day in Asia
- For recurring global meetings, rotate the inconvenient time slot fairly among all participants
For informational purposes only. Not financial, tax, or legal advice. Consult a qualified professional before making major decisions.