Daylight Saving Time Explained

Daylight Saving Time (DST) is the practice of setting clocks forward by one hour during warmer months so that darkness falls at a later time. Not all countries observe DST, and the dates of transition vary.

Who Observes DST?

• United States & Canada: Most states/provinces (except Arizona, Hawaii, Saskatchewan)
• European Union: All member states
• Australia: New South Wales, Victoria, South Australia, Tasmania, ACT
• Not observed: Most of Asia, Africa, and South America

When Do Clocks Change?

• US/Canada: Spring forward 2nd Sunday March; Fall back 1st Sunday November
• EU: Spring forward last Sunday March; Fall back last Sunday October
• Australia: Spring forward 1st Sunday October; Fall back 1st Sunday April

Impact on Time Differences

DST can change the time difference between cities. For example, New York to London is normally 5 hours, but during the weeks when only one has changed clocks, it can be 4 or 6 hours.

Tips for Managing DST

1. Always use timezone-aware datetime libraries
2. Store dates in UTC and convert for display
3. Use MeetZone to automatically handle DST transitions