Idaho is one of a handful of U.S. states split across two distinct time zones. If you're scheduling a call, planning a road trip, or checking what time it is, the answer depends entirely on which part of the state you're looking at. The northern panhandle operates on Pacific Time, while the southern majority of the state runs on Mountain Time.
Understanding this geographic split prevents missed flights, late meetings, and scheduling confusion. This guide breaks down the exact boundary, seasonal time changes, and how to tell which clock applies where.
The Two Idaho Time Zones Explained
The state divides roughly at the Salmon River, splitting administrative counties between two major North American zones.
- Mountain Time Zone (MT): Covers roughly the southern three-quarters of the state, including major population hubs like Boise, Idaho Falls, Pocatello, Twin Falls, and Sun Valley. This zone operates on Mountain Standard Time (MST, UTC-7) during winter and Mountain Daylight Time (MDT, UTC-6) in the summer.
- Pacific Time Zone (PT): Covers the northern panhandle, including cities like Coeur d'Alene, Lewiston, Sandpoint, and Moscow. This zone uses Pacific Standard Time (PST, UTC-8) in winter and Pacific Daylight Time (PDT, UTC-7) in summer.
Because of this split, traveling straight south from Canada through Idaho's panhandle into the southern interior requires you to advance your clock by one hour once you cross the county boundary line.
The Boundary Line: Which Counties Are Where?
The demarcation line isn't a straight latitudinal or longitudinal cut. Instead, it follows county borders established by historical commerce routes and geographic barriers like the Salmon River.
All territory north of the Salmon River—specifically the ten northernmost counties—observes Pacific Time. These counties include:
- Boundary
- Bonner
- Kootenai
- Benewah
- Shoshone
- Latah
- Clearwater
- Nez Perce
- Lewis
- Idaho (the northern portion)
Every county south of that boundary operates on Mountain Time. If you're visiting the University of Idaho in Moscow, you're on Pacific Time. If you drive four hours south to Boise State University, you've crossed into Mountain Time.
Daylight Saving Time in Idaho
Like most of the United States, all of Idaho observes Daylight Saving Time (DST). Clocks spring forward by one hour on the second Sunday in March and fall back by one hour on the first Sunday in November.
Because both halves of the state observe DST, the one-hour gap between North Idaho and South Idaho remains constant year-round. Northern Idaho is always one hour behind Southern Idaho, regardless of the month.
For official tracking of the exact atomic time offsets, check the National Institute of Standards and Technology or reference global offsets via Time and Date.
Common Mistakes to Avoid
Travelers and remote workers frequently trip up on Idaho's schedule due to a few common misconceptions:
- Assuming state boundaries match time zones: Many assume state lines dictate time zones uniformly. Because Idaho shares long borders with Washington, Oregon, Nevada, Utah, Wyoming, and Montana, its time zones align with its neighbors rather than internal uniformity. North Idaho matches Washington and Oregon time, while South Idaho matches Utah and Montana time.
- Forgetting the one-hour internal jump: Driving across the state from Coeur d'Alene to Boise means losing an hour mid-trip without ever leaving Idaho.
- Confusing local business hours: If you're calling a state government office or a corporate branch in Idaho, always verify whether the office is located in Boise (Mountain) or Coeur d'Alene (Pacific) to avoid calling after hours.
Frequently Asked Questions
Why is Idaho split into two time zones?
The split dates back to late 19th-century railroad routing and economic ties. Northern Idaho's primary trade and transit corridors historically tied to Spokane, Washington, and Pacific ports, pushing that region into the Pacific Time Zone. Southern Idaho aligned its commerce with Utah and the Mountain West.
Has Idaho ever tried to move to a single time zone?
Yes. The Idaho Legislature has periodically debated or passed non-binding resolutions exploring a unified time zone—typically advocating for permanent Mountain Time statewide to boost tourism and business alignment. However, changing time zones requires federal approval from the U.S. Department of Transportation, and northern residents strongly prefer staying aligned with Pacific Northwest neighbors.
What time is it right now in Boise compared to New York?
Boise is in the Mountain Time Zone, making it two hours behind New York (Eastern Time). When it's noon in New York, it's 10:00 AM in Boise.
Do any parts of Idaho ignore Daylight Saving Time?
No. Every county in Idaho transitions between standard and daylight saving time in sync with federal schedules. No part of the state opts out like Arizona or Hawaii.
