Oregon Time Zone: Pacific and Mountain Exceptions
Get a clear, accurate explanation with examples and useful comparisons. Oregon Time Zone: Pacific and Mountain Exceptions.
Oregon Time Zone: Pacific and Mountain Exceptions
Oregon uses two time zones
Most Oregon communities, including Portland, Salem, Eugene and Bend, use Pacific Time (PST in winter, PDT in summer). Parts of eastern Malheur County, including Ontario, use Mountain Time (MST/MDT). The time-zone boundary is geographic, not simply an east–west half-state divide.
| Oregon city or area | Time family | Winter UTC offset | Summer UTC offset |
| Portland, Salem, Eugene | Pacific | UTC−08:00 | UTC−07:00 |
| Ontario and parts of Malheur County | Mountain | UTC−07:00 | UTC−06:00 |
When does Oregon change clocks?
Oregon’s time-zone regions observe the main US daylight-saving transition dates. In 2026, most clocks went forward on March 8 and back on November 1 at 2 a.m. local time. The two-zone difference persists across the seasonal changes.
Example for cross-state travel
If a meeting starts at 2:00 p.m. in Portland, it is 3:00 p.m. in Ontario on an ordinary date when the respective zones follow the same seasonal schedule. This matters for trips toward the Idaho border and for appointments with organizations based in eastern Oregon.
How to set a device correctly
Use America/Los_Angeles for Portland and most of Oregon, or America/Boise for Ontario and the applicable Mountain Time communities. A device that only says “Oregon” may hide the exception. Check your exact town or county.
Frequently asked questions
Is Portland in Pacific Time?
Yes, Portland observes Pacific Time.
Is any part of Oregon in Mountain Time?
Yes. Parts of Malheur County, including Ontario, follow Mountain Time.
Is Oregon always one hour behind Idaho?
No. The answer depends on the Idaho destination; Idaho also spans multiple zones.
Why the Oregon–Idaho border can surprise travelers
Ontario, Oregon is near Boise, Idaho, and uses Mountain Time, so visitors can keep the same clock for that particular trip. Portland, Oregon uses Pacific Time, one hour behind Ontario. Other Idaho areas follow Pacific Time, so state borders by themselves are not enough to identify an offset. A reliable travel plan should record the town where each booking actually takes place, including restaurants and hotels, rather than assuming the departure zone carries over to the destination.
For an online event with participants in both Portland and Ontario, the organizer should identify the event city and write the time as Pacific or Mountain. A date-aware calendar normally displays the converted time for every attendee. A plain-text event poster saying “7 PM Oregon” is not specific enough to be universally correct.
Related time guides
These related guides answer adjacent questions without repeating the focus of this page: