Honestly, if you've lived in the Willamette Valley for more than a week, you know the "Portland rain" trope is only half the story. People think it's just a constant, gray drizzle from October to May. But when you look at the weather in lake oswego 10 days out, the reality is way more nuanced—and frankly, a lot more interesting than just carrying an umbrella.
Right now, we are sitting in that weird mid-January pocket where the air feels like it’s holding its breath.
As of Sunday night, January 18, 2026, it is 34°F outside. It’s a crisp, clear-ish night with about 80% humidity, making that air bite just a little harder than the thermometer suggests. If you're out for a late walk near Millennium Plaza Park, it actually feels more like 27°F because of a steady 9 mph breeze kicking in from the northeast.
The Immediate Outlook: Sun, Then the Switch
Tomorrow, Monday, January 19, looks like a winner for anyone who hates the typical Northwest gloom. We’re looking at a high of 47°F and total sun. It’s going to be one of those brilliant, "bluebird" winter days where the lake looks like glass. But keep your coat handy; the low is dropping to 30°F at night.
Tuesday and Wednesday (January 20-21) keep that trend going. Highs stay around 49°F. It’s mostly cloudy, but dry enough to hit the trails at Tryon Creek without becoming a mud ball.
🔗 Read more: Finding the Right Word That Starts With AJ for Games and Everyday Writing
Then, the classic Oregon "Big Dark" returns.
By Thursday, January 22, the wind shifts. It stops coming from the cold northeast and starts blowing in from the south. That brings the moisture. We’re looking at a transition from "mostly cloudy" to "light rain" overnight, with highs dropping slightly to 44°F.
Why Weather in lake oswego 10 days is Never Just One Forecast
Lake Oswego has these weird little microclimates. If you’re up in the Mountain Park neighborhood, you’re essentially living on an extinct volcano (literally, Mount Sylvania). You might see a dusting of snow while the people down by the George Rogers Park docks are just getting a cold rain.
Between Friday, January 23, and Sunday, January 25, we enter a very consistent wet cycle.
💡 You might also like: Is there actually a legal age to stay home alone? What parents need to know
- Highs: Solid 46°F every single day.
- Lows: Creeping up from 37°F to 40°F.
- Precipitation: About a 20% to 25% chance of light rain daily.
It’s not a deluge. It’s that "misty-moisty" stuff that locals just ignore while wearing a Patagonia vest.
The Snow Question
Everyone always asks: will it snow?
Looking at the weather in lake oswego 10 days forecast, there are "trace" mentions of snow types in the precipitation mix for Saturday night (Jan 24) and Monday night (Jan 26). But don't go buying out the kale at New Seasons just yet. The ground is likely too warm, and the lows are hovering right at or above freezing (39°F to 40°F). In Lake Oswego, you usually need a perfect collision of a Fraser Valley outflow (cold air from the north) and a moisture plume from the Pacific. This week, we have the moisture, but the "cold" isn't quite deep enough for a repeat of the 2024 ice storm.
Late Next Week: The Humidity Hangover
By the time we hit Tuesday, January 27, the temperatures actually start climbing. We’re looking at a high of 50°F.
📖 Related: The Long Haired Russian Cat Explained: Why the Siberian is Basically a Living Legend
It’ll be overcast and gray, with 75% humidity. It's that heavy air that makes your hair go crazy and keeps the moss on your North Shore roof very happy. Historically, January in Lake Oswego sees about 9.2 hours of daylight, but let’s be real—with the cloud cover we're expecting next week, it’ll feel like the sun sets at 3:00 PM.
Practical Survival Tips for the Next 10 Days
If you're planning your week, here's how to actually handle this forecast:
- Monday is your "Outdoor Day": If you have garden cleanup or want to walk the lake loop, do it Monday. It’s the last guaranteed dry day before the clouds settle in for the long haul.
- Check your gutters by Thursday: The rain starting Thursday night isn't heavy, but January rain in Oregon tends to find the clogs you ignored in November.
- Layers over Umbrellas: With wind speeds between 3 and 13 mph over the next week, umbrellas are mostly useless ornaments. A decent shell with a hood is the unofficial LO uniform for a reason.
- Morning Ice: Even though it's sunny early in the week, those 30°F lows on Monday and Tuesday night mean black ice on the back roads near Iron Mountain. Take it slow on the curves.
The weather in lake oswego 10 days outlook shows a classic transition. We’re moving from a cold, dry continental air mass into a warmer, wetter maritime flow. It’s the heartbeat of the Pacific Northwest winter.
Next Steps for Lake Oswego Residents:
- Schedule outdoor activities for Monday, Jan 19, to take advantage of the 47°F sunny peak.
- Prepare for rain gear starting the evening of Thursday, Jan 22, as the shift to light rain begins.
- Monitor overnight temperatures on Jan 24 and Jan 26 if you have sensitive plants, as the rain-snow mix chance rises during those windows.