Phoenix, United States

Phoenix keeps Mountain Standard Time (MST) at UTC−7 year-round — Arizona is one of the few U.S. states that does not observe daylight saving time. This means Phoenix aligns with PDT cities in summer and MST cities in winter.

During summer, Phoenix shares the same clock as Los Angeles and San Francisco. In winter it matches Denver. This shifting alignment can catch visitors off guard when scheduling cross-state calls.

Rapid growth in semiconductor manufacturing and data center construction has turned Phoenix into a key tech corridor, increasing the city’s need for reliable global time coordination.