Sources & Methodology
The live clock, MST/UTC−7 status, visitor comparison and time differences update automatically. The sources below document Arizona's no-DST rule and the time-zone data used for Phoenix.
Arizona daylight-saving history: the Arizona State Library notes that Arizona made the permanent change back to Standard Time in 1968. NIST guidance: NIST identifies Arizona as an area that does not observe daylight saving time for clock-setting purposes. Official U.S. time: Time.gov is operated by NIST. Time-zone rules: IANA tzdb provides the America/Phoenix rules used by standards-compliant runtime libraries.
Reviewed August 18, 2026. IANA architecture baseline: tzdb 2026c. This URL is evergreen; live time, date, MST/UTC−7 status, UTC-offset comparisons and visitor-local calculations update automatically.