Phoenix and Las Vegas are usually on the same time or 1 hour apart. Phoenix uses Mountain Standard Time (MST, UTC-7) year-round, while Las Vegas uses Pacific Time (PST/PDT, UTC-8/-7). During standard time, Las Vegas is 1 hour behind; during daylight saving time, both cities are the same.
Arizona (except Navajo Nation) does not observe daylight saving time, so the difference varies seasonally.
Any time generally works! Since both cities are usually the same or just 1 hour apart, you can call during normal business hours with minimal adjustment needed.
Phoenix and Las Vegas are desert cities with hot climates. The drive between them takes about 4.5-5 hours, making Las Vegas a popular weekend destination for Phoenix residents. Many flights connect the cities daily.