When it is 1 PM Eastern Standard Time (EST) during the winter months, the local time in most of Arizona is 11 AM Mountain Standard Time (MST). That puts the Grand Canyon State two hours behind the East Coast. If you are scheduling a phone call, booking a flight, or planning a remote meeting across state lines, getting this calculation right depends on whether daylight saving time is active.
Arizona operates under a unique set of timekeeping rules that differ from most of the United States. While 48 states shift their clocks twice a year, Arizona largely stays put on standard time. Understanding how this system works prevents missed appointments and awkward scheduling errors throughout the year.
Why Arizona Does Not Observe Daylight Saving Time
Most of the United States adopted daylight saving time to extend evening daylight during warmer months. Arizona tried it out in 1967 following the passage of the Uniform Time Act, but state lawmakers quickly abandoned the practice after just one year.
The primary driver behind Arizona's decision is climate. Summers in the desert bring extreme heat, where afternoon temperatures routinely soar past 100 degrees Fahrenheit. If the state shifted clocks forward, residents would endure an extra hour of intense sunlight late into the evening, delaying the cooling relief that arrives after sunset. Keeping clocks on standard time year-round helps keep evening routines aligned with slightly cooler temperatures.
According to historical records from the National Institute of Standards and Technology, states retain the legal authority to opt out of daylight saving time under federal law, provided the entire state remains uniform unless specific federal tribal exemptions apply.
Winter vs Summer: How the Time Gap Changes
The time difference between Arizona and the East Coast shifts depending on the time of year because Eastern states observe daylight saving time while Arizona does not.
During winter, when EST and MST are active from November to March, Arizona is exactly two hours behind New York and Washington, D.C. When the clock strikes 1 PM EST, it is 11 AM in Phoenix, Tucson, and Flagstaff.
During summer, from March to November, the East Coast switches to Eastern Daylight Time (EDT), moving one hour ahead to UTC-4. Because Arizona refuses to change its clocks, it stays on MST (UTC-7). As a result, the time gap shrinks. When it is 1 PM EDT in the summer, Arizona time is 12 PM noon, making the state only one hour behind the East Coast.
The Navajo Nation Exception
Arizona's time zone map is not entirely uniform. While the vast majority of the state ignores daylight saving time, the Navajo Nation carves out a major exception.
The Navajo reservation spans northeastern Arizona and extends into parts of New Mexico and Utah. To maintain consistent timekeeping across tribal lands that cross state borders, the Navajo Nation observes daylight saving time. When the rest of the country springs forward in March, residents on the Arizona portion of the Navajo reservation move their clocks forward too.
Just a few miles away, the Hopi Reservation—which is entirely surrounded by the Navajo Nation—does not observe daylight saving time. Driving through this region during the summer can lead to a confusing loop where travelers cross invisible boundaries and have to adjust their watches multiple times within a short distance.
Practical Tips for Cross-Country Scheduling
Coordinating schedules with individuals or businesses in Arizona requires intentional communication. Relying on automated calendar tools helps, but human error still causes missed meetings.
- Specify the timezone offset: Instead of writing "let's meet at 1 PM," specify "1 PM Eastern" or "11 AM Arizona time" to remove ambiguity.
- Check device settings: Modern smartphones and computers automatically recognize Arizona's fixed time zone, but manual calendar entries or older software can sometimes miscalculate the shift when daylight saving time begins or ends.
- Confirm tribal appointments: If you are scheduling an event or visit within the Navajo Nation during the summer, double-check whether the local contact operates on tribal time (which follows daylight saving) or standard Arizona time.
Frequently Asked Questions
What time is it in Arizona when it is 1 PM EDT in the summer?
In the summer, when the East Coast is on Eastern Daylight Time, Arizona is one hour behind. When it is 1 PM EDT, it is 12 PM noon in Arizona.
Does the entire state of Arizona ignore daylight saving time?
No. While nearly 99 percent of the state stays on Mountain Standard Time year-round, the Navajo Nation in northeastern Arizona observes daylight saving time.
Why does Arizona stay on standard time?
State officials dropped daylight saving time in 1967 because extending daylight into the hot summer evenings prolonged high cooling costs and made outdoor work miserable during peak heat.
How many hours behind the East Coast is Arizona?
Arizona is two hours behind the East Coast during the winter months (EST) and one hour behind during the summer months (EDT).
