Twice every year, global businesses run into the 'Daylight Saving Disconnect'. In the United States, clocks 'spring forward' on the second Sunday in March. In the United Kingdom and the European Union, the transition occurs on the last Sunday in March—two or three weeks later.
During this multi-week window, the standard time difference between New York and London shrinks from 5 hours to 4 hours. Recurring calendar invites that were set months in advance suddenly collide with lunch breaks or overlap with other appointments.
To make matters more complex, countries like Japan, Singapore, India, and China do not observe Daylight Saving Time at all. Meanwhile, Southern Hemisphere regions like Australia and New Zealand shift in the exact opposite direction—falling back when the north springs forward.
Why Static Offset Calculators Fail
If you rely on a converter that uses static offsets (e.g. assuming London is always UTC+0 or New York is always UTC-5), you will calculate incorrect meeting times whenever you plan across a transition date.
The Solution: Modern IANA Time Zone Identifiers. Meeting Planner AI queries native browser IANA engines (`Intl.DateTimeFormat`) calibrated to your chosen future meeting date. Whether your call is tomorrow or next month, the displayed hours always reflect the exact legal offsets in effect on that day.