Phoenix and Denver share the same time during standard time (November to March). Both use Mountain Standard Time (MST, UTC-7).
However, Arizona does not observe daylight saving time. During Denver's daylight saving time (March to November), Denver is 1 hour ahead of Phoenix as Denver moves to UTC-6 while Phoenix stays at UTC-7.
Any time during business hours works year-round. During DST, 8:00 AM Phoenix time is 9:00 AM in Denver.
Phoenix and Denver are both Mountain West cities but handle DST differently. This makes Arizona unique among most US states and creates seasonal timing variations between these neighboring regions.