The first chill of December paints a silver sheen across lawns and windshields across Portland, Oregon this morning. The air feels crisp, calm, and just cold enough to bite — a quiet calm before the next round of rain and early winter dampness moves through early this week.
According to the National Weather Service in Portland, areas of frost will form between 7 and 9 a.m. Monday, especially across the Columbia River Basin, Gresham, and Hillsboro. Temperatures dip into the mid-30s, making slick spots possible on elevated bridges and shaded streets. Calm conditions and clear skies create perfect frost-making weather before a moisture shift begins to arrive late Monday.
By Monday night, clouds thicken, and rain develops after 4 p.m., with a 60% chance of showers through Tuesday morning. While totals will stay modest — generally under a quarter inch — timing could lead to slow commutes across I-5, I-205, and I-84, especially during the Tuesday morning rush. Temperatures remain mild, with highs around 49°F and lows near 40°F.
After Tuesday’s rain passes, midweek turns mostly dry and seasonably cool. Wednesday and Thursday bring partly sunny skies and highs in the upper 40s, perfect for holiday errands or outdoor decorating before another system edges closer Friday.
Five-Day Outlook (Portland, OR):
- Monday: Frost early, partly sunny, high 47°F, low 40°F.
- Tuesday: Rain likely, high 49°F, low 39°F.
- Wednesday: Mostly cloudy, high 48°F, low 37°F.
- Thursday: Slight rain chance, high 47°F, low 42°F.
- Friday: Rain likely, high 53°F, low 44°F.
