A clock time without a named time zone is incomplete information when people or systems cross regions.
Store or communicate an instant together with…
Store or communicate an instant together with its time zone or offset. Display it in the reader’s local zone only when that behavior is intentional.
Expect daylight-saving transitions to change offsets during…
Expect daylight-saving transitions to change offsets during the year. Prefer IANA names such as Europe/London over a fixed label such as GMT when rules matter.
For appointments, include the date, clock time,…
For appointments, include the date, clock time, zone name, and a link to the authoritative calendar event.
Use the related tool carefully
This guide is paired with a browser-only utility. The tool is a practical aid for small examples and inspection; it is not a substitute for application testing, a formal data pipeline, or professional review where the decision has higher consequences.
Open the related Time Zone Converter