A good meeting time needs a date.

“Let’s meet at 9” works when everyone shares the same clock. Across time zones, an invitation needs three pieces of information: a calendar date, a local time, and the time zone that gives that local time meaning.

An offset is a snapshot

A UTC offset describes how far a local clock is ahead of or behind UTC at a particular instant. A named time zone, such as America/New_York, also carries the rules that determine which offset applies on a particular date. Those rules can include daylight saving and historical changes.

That is why choosing “New York” is more useful for planning a future meeting than writing a fixed “UTC−5.” A fixed offset may describe one season correctly and another incorrectly. The IANA Time Zone Database records these rules and is updated when political decisions change them.

The awkward weeks in between

Two places can both observe daylight saving and still change their clocks on different weekends. For example, a New York–London meeting can temporarily shift by an hour during the gap between their seasonal transitions. Never assume a familiar difference applies to a future date: enter that date in a converter.

Some local times happen twice. Others never happen.

When a clock jumps forward, it skips an interval of local times. When it moves back, it repeats an interval. A meeting at a repeated time needs a decision about which occurrence is intended. Our converter rejects skipped times and asks you to choose the earlier or later occurrence for a repeated one.

Make the next invitation easier

Use the time zone converter to compare the date in each participant’s location. Download the one-hour calendar event, which stores a single UTC instant. For recurring meetings, decide whose local time should remain fixed and create the recurrence in that location’s time zone in your calendar app.

Technical reference: Temporal’s handling of zoned dates and repeated or skipped times.