Daylight Saving Time (DST): How It Disrupts Meetings & How to Prevent It

Daylight Saving Time (DST) is the practice of advancing clocks by 1 hour during summer months so that evenings have more daylight. Most of the US, Canada, and Europe observe DST, while Japan, China, and most of Asia do not.

The key problem for global teams: the US and EU switch DST on different dates. The US typically switches in early March and November, while Europe switches in late March and October. During the 2-3 week gap between these switches, the time difference between the US and Europe changes by 1 hour.

Imagine you have a weekly Monday 3:00 PM ET call with a team in London. In winter, ET is UTC-5 and London is UTC+0, giving a 5-hour difference. Your 3:00 PM ET = 8:00 PM London. After the US switches to EDT (UTC-4) but before Europe switches, the difference becomes 4 hours. Now your 3:00 PM EDT = 7:00 PM London — 1 hour earlier than expected.

This 1-hour shift often goes unnoticed by automated calendar apps that respect timezone names (like America/New_York), but it catches many people off guard when they hardcode UTC offsets in spreadsheets or email threads.

The safest approach is to always reference timezone names (e.g., America/New_York, Europe/London) rather than fixed UTC offsets when scheduling recurring meetings. Calendar apps like Google Calendar do this automatically.

Use our DST Calendar tool to check upcoming DST switch dates for major countries. Before scheduling important meetings near the March/November switch periods, verify that the time still works for all participants after the switch.