You’ve heard the jokes about Oregon. People think we grow gills by February. But if you’re looking at the 14 day forecast Eugene Oregon right now, things are looking a little... weird. Honestly, it’s not the soggy mess you’d expect for mid-January.
We are currently sitting in a strange bubble. As of Saturday, January 17, 2026, the southern Willamette Valley is trapped under a massive high-pressure ridge. It sounds great—sunny days, right? Well, sort of. Today is a crisp 48°F with bright sun, but there is a catch. The air is stagnant.
The Inversion Trap and Your Commute
Basically, we have a "subsidence inversion." That’s a fancy weather term for a warm lid of air sitting on top of the cold air in the valley. It traps everything. Smoke, dust, and—most importantly for anyone driving the I-5 corridor—fog.
The National Weather Service in Portland has already issued an Air Stagnation Advisory for the Eugene area, effective through 10 AM Tuesday, January 20. If you have asthma or just hate breathing "thick" air, this isn't your favorite week.
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Here is what the next few days look like on the ground:
- Sunday, Jan 18: Mostly cloudy with a high of 49°F. Expect dense fog in the morning.
- MLK Day, Jan 19: Partly sunny. Chilly morning at 28°F, warming to 50°F.
- Tuesday, Jan 20: More of the same. Highs around 50°F, lows dipping to 28°F.
Driving to work? Watch out for frost. Even though the days feel "warm" for January, those overnight freezes are real. North winds at about 3 mph aren't enough to clear out the valley gunk, so the fog will likely linger until lunch most days.
When the Rain Finally Returns
The high pressure won't last forever. Most models show the ridge breaking down toward the end of next week. By Thursday, January 22, the clouds settle in for good.
We are looking at a 20% chance of rain by Friday, which jumps significantly as we head into next weekend. Saturday, January 24, actually shows a mix of snow and rain showers with a high of 45°F. Don't buy a sled yet, though. In Eugene, "snow" usually means "slush that disappears in twenty minutes."
The real shift happens around January 27. We are tracking a 70% chance of rain that Tuesday night. It’s a return to the classic Eugene winter—damp, grey, and 47°F.
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Why the Snowpack Matters
You might have noticed the Cascades look a little brown. Zac Ziegler over at KLCC recently reported that western Oregon’s snowpack is sitting at less than 50% of its normal levels. While the valley stays dry and foggy, the mountains are desperate for a real storm. This upcoming shift in the 14 day forecast Eugene Oregon might bring some relief to Willamette Pass, but it looks more like "wet" than "white" for now.
What to Pack (or Wear)
If you’re visiting or just planning your week, forget the heavy parka. You need layers.
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- A light puffer: Perfect for those 29°F mornings.
- Waterproof shell: Keep it in the car for when the ridge breaks next Friday.
- Good tires: Between the freezing fog advisories and the air stagnation, the roads are slicker than they look.
The valley is beautiful when the sun hits the frost on the Spencer Butte trails, but that same clear sky means the heat escapes into space the second the sun goes down. Stay warm.
Actionable Steps for the Next 14 Days
Check your air filters. With the Air Stagnation Advisory in place, your HVAC system is working overtime to keep the valley haze out of your living room. If you’re planning a trip over the McKenzie or Willamette passes, check the ODOT TripCheck cameras before you head out; the transition from valley fog to mountain sun is often abrupt and blinding. Finally, enjoy the dry afternoons through Wednesday—because once the rain returns on the 23rd, it looks like it's staying through the end of the month.