Denver uses Mountain Time (America/Denver), MST or MDT, unlike most of Arizona.
Detecting your timezone for a personal comparison…
Now
Colorado observes daylight saving. In summer Denver matches Phoenix; in winter it is an hour behind Phoenix. That seasonal pairing is a frequent source of domestic meeting errors.
Denver uses America/Denver. The current offset is UTC-06:00. Clocks on this page update from that IANA zone rather than from the server’s local time.
Denver, United States is in Mountain Standard Time (America/Denver). Denver uses Mountain Time (America/Denver), MST or MDT, unlike most of Arizona.
Daylight saving time is in effect America/Denver observes daylight saving (MDT, UTC−06:00). Arizona generally does not.
At this moment the offset difference is -01:00 hours relative to UTC labels, meaning Denver compared with Chicago can be converted in the time zone converter using America/Denver and America/Chicago. Daylight saving on either side is applied automatically.