Idaho sits in two distinct time zones, a unique geographical split that often catches travelers and remote workers off guard. Most of the state operates on Mountain Time, while the northern panhandle sits on Pacific Time. Understanding this division is essential for scheduling calls, travel planning, and managing business across state lines.
The boundary splitting Idaho runs along the Salmon River from the Oregon border down to Montana. Everything north of that geographic line observes Pacific Standard Time or Pacific Daylight Time, aligning with Washington and Oregon. Everything south of the Salmon River—including Boise, Twin Falls, Idaho Falls, and Pocatello—operates on Mountain Standard Time or Mountain Daylight Time, aligning with Utah and Nevada.
Why Idaho Is Split Into Two Time Zones
The state's dual time zone structure dates back to 1918 when the original Interstate Commerce Commission established standard time zones in the United States. Initially, the entire state of Idaho was placed in the Mountain Time Zone.
However, commerce and transportation ties in the northern panhandle connected residents more closely with Spokane, Washington, and the Pacific Northwest than with southern Idaho hubs like Boise. Panhandle leaders petitioned for a change, and in 1923, the boundary was shifted north. Residents in the northern counties wanted their business hours, train schedules, and radio broadcasts to match their primary economic partners in Washington.
Today, this division remains codified by the U.S. Department of Transportation under Title 49 of the Code of Federal Regulations. The split affects 10 northern counties in the Pacific Time Zone and 34 southern counties in the Mountain Time Zone.
Current Time Differences Within Idaho
When you cross from one side of Idaho to the other, you change your watch by one hour. For example, if it's 2:00 PM in Boise, it's 1:00 PM in Coeur d'Alene or Lewiston.
This internal time difference creates unique logistical challenges for state agencies, universities, and businesses operating statewide. The Idaho Legislature must account for the one-hour gap when scheduling committee hearings or coordinating emergency responses between northern and southern offices. School districts in the panhandle follow Pacific Time, while state universities in Moscow (UI) and Boise (BSU) must synchronize academic calendars and athletic events across the boundary.
- Mountain Time Zone (Southern Idaho): Boise, Meridian, Nampa, Idaho Falls, Pocatello, Twin Falls, Sun Valley.
- Pacific Time Zone (Northern Idaho): Coeur d'Alene, Lewiston, Sandpoint, Post Falls, Moscow.
Daylight Saving Time Observations
Like most of the United States, both regions of Idaho observe Daylight Saving Time. Clocks spring forward one hour on the second Sunday in March and fall back one hour on the first Sunday in November.
Because both northern and southern Idaho observe the seasonal time change, the one-hour gap between the two halves of the state remains constant year-round. You don't have to worry about the gap closing during summer months; the panhandle and the southern plains shift their clocks on the exact same schedule.
For businesses dealing with states that do not observe Daylight Saving Time—such as Arizona or parts of neighboring jurisdictions—scheduling requires extra attention during the spring and autumn transition weeks.
Practical Tips for Travelers and Remote Workers
If you're planning a road trip across Idaho or coordinating meetings with clients spread across the state, keep these practical steps in mind:
- Check your meeting software: Calendar applications like Google Calendar or Microsoft Outlook automatically adjust for time zones based on your invitee's location settings, but manual verification is safer when dealing with cross-border Idaho appointments.
- Confirm travel itineraries: When booking flights into Boise Airport (BOI) and connecting to regional flights or buses heading to the panhandle, double-check departure times to avoid missing connections due to the one-hour shift.
- Note the county boundary: If you're driving north on U.S. Route 95 past Riggins, pay attention to road signs indicating you are crossing the time zone boundary.
Frequently Asked Questions
What time zone is Boise, Idaho in?
Boise is in the Mountain Time Zone (UTC-7 in standard time, UTC-6 during daylight saving time).
What major cities in Idaho are on Pacific Time?
Coeur d'Alene, Lewiston, Sandpoint, and Moscow are the largest communities in Idaho's Pacific Time Zone.
Why doesn't the whole state use the same time?
Economic and transportation ties drove the split. Northern Idahoans historically traded and traveled more with Washington State than with southern Idaho, prompting a petition to move the panhandle to Pacific Time in 1923.
Does Idaho plan to abolish Daylight Saving Time?
Lawmakers have introduced bills in past legislative sessions to keep Idaho on standard or daylight time permanently, but no changes have been enacted. Both regions continue to follow federal daylight saving schedules.
