Major Time Zones (from UTC)
| Zone | UTC Offset | Major Cities |
|---|
| Pacific (PT) | UTC-8 / UTC-7 (DST) | Los Angeles, Vancouver |
| Mountain (MT) | UTC-7 / UTC-6 (DST) | Denver, Phoenix* |
| Central (CT) | UTC-6 / UTC-5 (DST) | Chicago, Mexico City |
| Eastern (ET) | UTC-5 / UTC-4 (DST) | New York, Toronto |
| GMT/BST | UTC+0 / UTC+1 (DST) | London, Lisbon |
| CET | UTC+1 / UTC+2 (DST) | Berlin, Paris, Rome |
| IST | UTC+5:30 | Mumbai, New Delhi — no DST |
| CST (China) | UTC+8 | Beijing, Shanghai — no DST |
Daylight Saving Time
| Region | Spring Forward | Fall Back |
|---|
| US/Canada | 2nd Sunday in March | 1st Sunday in November |
| Europe | Last Sunday in March | Last Sunday in October |
| No DST | Most of Asia, Africa, South America — check per country |
Scheduling Across Zones
| Tip | Why |
|---|
| Always specify the zone | "2 PM ET" not "2 PM" — avoids ambiguity |
| Use UTC internally | Teams across zones should standardize on UTC for schedules |
| Check DST dates | Europe and US switch on different weekends — a 2-week window where offsets are wrong |
Pro Tip: When scheduling across time zones, find the window that works for everyone and lock it in as a recurring slot. Moving meetings around is exponentially harder across zones. 8 AM PT / 11 AM ET / 4 PM GMT is the magic window that works for US + Europe.