Non-DST region inside a DST country

Arizona observes no DST while the rest of US Mountain does; Queensland differs from New South Wales. A country name or a 'Mountain Time' label is ambiguous for half the year.

Class

Case to account for

Affects

1 conversion

Detection

DST rules resolved at zone level disagree with a country/offset label.

Mitigation

Resolve by IANA zone (America/Phoenix vs America/Denver), never by country or offset.

Affected conversions

Timestamp + zonehour-of-week slot

OPEN