Oregon – Cold air presses into the valleys, exhaust hangs low, and a faint haze blurs distant hills as eastern Oregon closes out 2025 under a stubborn inversion. Air quality concerns and freezing fog are shaping daily routines across the Pendleton area as New Year’s Eve unfolds.
According to the National Weather Service in Pendleton, an Air Stagnation Advisory remains in effect through midday Thursday for much of north-central and eastern Oregon. Light winds and a strong temperature inversion are trapping pollutants near the surface, allowing air quality to deteriorate through today and into New Year’s Day.
In Pendleton, Hermiston, and nearby communities, morning temperatures have dipped near 20 degrees with mist and patchy freezing fog reported. Visibility has been reduced in spots along I-84, Highway 11, and rural roads through the Columbia Basin. Slick patches are possible on bridges and shaded roadways where fog freezes on contact.
Sensitive groups, including those with asthma or heart conditions, are urged to limit outdoor activity. Residents are also encouraged to avoid wood burning and reduce vehicle idling while stagnant conditions persist. For now, the cold, still air remains locked in place.
Change arrives as 2026 begins. Rain chances increase late New Year’s Day into Friday, helping mix out the inversion and gradually improve air quality. Temperatures climb into the 40s by Friday afternoon, easing freezing concerns but introducing wet travel conditions instead.
Heading into the first weekend of 2026, scattered rain showers continue across eastern Oregon. While snow is not expected in Pendleton, higher elevations of the Blue Mountains may see winter weather impacts that affect regional travel.
Additional advisories may be issued if stagnation lingers longer than expected. Noticing haze or fog where you live? Let us know how conditions look in your neighborhood.
Five-Day Outlook for Pendleton, Oregon
• Today: Cold with freezing fog early, patchy sun; highs near 37
• New Year’s Day: Cloudy, patchy freezing fog; highs near 37
• Friday: Chance of rain, milder; highs near 45
• Saturday: Scattered rain showers; highs near 51
• Sunday: Mostly cloudy with a chance of rain; highs near 52
