Time in Oregon is divided into two zones, with the vast majority in thePacific Time Zone. Most of sparsely populatedMalheur County, including its largest city,Ontario, and its county seat,Vale, are in theMountain Time Zone due to their proximity toBoise, Idaho. The time zone division occurs at the southwest corner of township 35 S, range 37 E (approximately 42.597 degrees north latitude), continuing east to the state line, then south along theOregon–Idaho border to theNevada state line.[1]
In 2019, theOregon Senate passed a bill that would put the state (except Malheur County) on year-rounddaylight saving time, effectively moving Oregon full time to Mountain Standard Time (UTC−7). The bill has not yet been considered by theOregon House of Representatives. Similar proposals have been approved inWashington andCalifornia; all would need approval of theU.S. Congress.
In theIANA time zone database, Oregon is contained in two zones:
| c.c.* | coordinates* | TZ* | comments* | UTC offset | UTC offset DST | Note |
|---|---|---|---|---|---|---|
| US | +340308−1181434 | America/Los_Angeles | Pacific | −08:00 | −07:00 | All except northern 4/5 ofMalheur County |
| US | +433649−1161209 | America/Boise | Mountain – ID (south), OR (east) | −07:00 | −06:00 | Northern 4/5 ofMalheur County only |