Everything you need to know about DST and how it affects your international meetings. Learn when clocks change and how to avoid scheduling conflicts during transitions.
Understanding Daylight Saving Time: A Complete Guide
Daylight Saving Time (DST) is one of the most confusing aspects of time zone management. This guide explains everything you need to know.
What is Daylight Saving Time?
DST is the practice of moving clocks forward by one hour during warmer months so that evenings have more daylight. In most regions that observe it, clocks "spring forward" in March/April and "fall back" in October/November.
Which Countries Observe DST?
Not all countries observe Daylight Saving Time:
Countries that DO observe DST:
- Most of the United States and Canada
- Most European countries
- Parts of Australia
- New Zealand
- Parts of the Middle East
Countries that DON'T observe DST:
- Most of Asia (China, Japan, India, etc.)
- Most of Africa
- Most of South America
- Russia (since 2014)
- Arizona and Hawaii in the US
When Does DST Change Happen?
DST transitions don't happen at the same time worldwide:
- United States: Second Sunday of March / First Sunday of November
- European Union: Last Sunday of March / Last Sunday of October
- Australia: First Sunday of October / First Sunday of April (southern hemisphere - opposite seasons!)
This means there are brief periods each year when the time difference between regions temporarily changes.
The DST "Twilight Zone"
For about 2-3 weeks twice a year, the time difference between regions changes. For example:
- Normally, New York is 5 hours behind London
- During the two weeks when Europe has changed but the US hasn't, it's only 4 hours
- This can cause confusion for recurring meetings
How DST Affects Your Meetings
If you have a recurring weekly meeting:
- Before DST change: Meeting at 3 PM London = 10 AM New York (5-hour difference)
- After US "springs forward": Meeting at 3 PM London = 11 AM New York (4-hour difference temporarily)
- After both change: Back to 5-hour difference
This is why it's crucial to use timezone-aware scheduling tools rather than just remembering time differences.
Handling DST in Scheduling
Modern tools like Whenest automatically handle DST:
- When you schedule a meeting for a future date, the correct local times are calculated even if DST changes occur between now and then
- DST alerts warn you when upcoming changes might affect your scheduled meetings
- Calendar exports (ICS files) use UTC time, so the event appears at the correct local time regardless of DST
If you need quick conversions for future dates, the time zone converter will show you accurate, DST-aware results.
See how Whenest works for a step-by-step guide to scheduling DST-aware meetings.
Best Practices for DST
- Use timezone-aware tools: Always use tools that handle DST automatically
- Check DST dates: Be aware of when transitions occur in regions relevant to you
- Communicate clearly: When DST is approaching, confirm meeting times with participants
- Use UTC for documentation: When writing down times for reference, include the UTC equivalent
The Future of DST
There's growing momentum to end the twice-yearly clock changes. The European Union voted to abolish DST (though implementation has been delayed), and various US states have proposed permanent standard or daylight time.
Until then, understanding how DST works remains essential for anyone coordinating across time zones. Start using Whenest to automatically handle DST for all your meetings, or check our FAQ for more answers about time zone scheduling.