Why does the time zone matter?¶

One moment appears as different clock values in different zones, and events near midnight can fall on different dates. Without the zone, a timestamp can be misplaced by hours.

Storage and display may use different zones¶

Cloud services often store UTC and convert for viewers; devices may store local time; exports can convert again or remove the offset. Daylight-saving rules change the relationship by date and location, so apparently contradictory records can represent the same moment.

Make conversion reproducible¶

Preserve the original value, suffix or offset and establish source and display zones. For conversion record original value and zone, target zone, date-specific rule, method and converted value.

Do not label a time UTC or local because it appears likely; support it with configuration or documentation.