Interactive publication
Back to the catalogueTime-zone databaseCase 03 of 06
Historical offset changes
Before standardization zones ran on local mean time, and countries have changed their base offset since (Samoa skipped 2011-12-30 crossing the date line; Venezuela and North Korea shifted by 30 minutes). Old timestamps need the historical offset, not today's.
Class
Case to account for
Affects
1 conversion
01
Detection
Instant predates a zone's offset change.
02
Mitigation
01
Use the full tz history (luxon/IANA carry it); never assume the current offset for a past instant.
03
Affected conversions
Timestamp + zonehour-of-week slot
OPEN