Weather in Eugene in December

The month to avoid. December is the month most people should skip in Eugene. You should expect rain on 20 days of the month, which is more days wet than dry.

December ranks 12 of 12 — near the bottom of Eugene's year. July is the month that works, and the swing between the two is 67 points, which is a different holiday rather than a slightly better one.

Rain on 20 of the month's 31 days, 9 of them heavy. At that frequency a wet-weather backup is not a contingency, it is the itinerary — book the indoor things first and treat the clear days as the bonus. Layers, and a genuinely waterproof outer — at 9.2 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 7 nights fall below freezing. Across the twenty years measured, the hottest December day reached 17.3 °C and the coldest night fell to -10.4 °C, and the wettest single day dropped 76 mm — roughly 31% of the month's rain in one day.

December is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest December on record still delivered 433 mm against 76 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 243 mm average is a reasonable planning figure, not a promise.

Wind is light at 0.4 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 93%, which at 9.2 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How December sits in the year

This is a turning point in the year — November and January sit on opposite sides of it, so the month contains the change rather than following it.

Daylight in December

December sits at the dark end of Eugene's year — 8.9 hours of daylight against 15.5 at midsummer, holding steady all month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

An inland climate

With no coast nearby, the year swings a fair way — 25.1 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

December in Eugene versus nearby

If Eugene is one option among several, the nearby comparison is worth making. Portland is close enough to be a coin toss — within a degree on temperature, the same number of rain days. Tri-Cities is a better bet in December — 2.5 °C cooler, 10 days less rain.

So: December is a compromise. July is 67 points better and is what Eugene is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Eugene

See all twelve months in Eugene, or where else to go in December.