Weather in Eugene in September

Prime time. September is about as good as Eugene gets. Highs average 25.4 °C, lows 11.3 °C, and rain falls on 6 days — nothing in the month is working against you.

September ranks 3 of 12 in Eugene. Only July scores clearly higher, and the difference is small enough to be settled by price rather than weather.

Rain falls on only 6 days, so an itinerary with no wet-weather fallback is a reasonable risk. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: 6 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest September day reached 38.4 °C and the coldest night fell to 5.2 °C, and the wettest single day dropped 59 mm — roughly 118% of the month's rain in one day.

This is the volatile part. September rainfall has ranged from 1 mm to 223 mm across the twenty years measured — a 222 mm spread around an average of 50 mm. The average is real but almost no individual September looks like it, so treat the figure as the middle of a wide range rather than a forecast.

Wind is light at 0.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 72%.

How September sits in the year

The month is on the way down: 2.3 °C cooler than August, with October dropping another 6.5 °C. The first week and the last are not the same trip. Rain is the thing that moves: October brings 6 days more of it, so the earlier half of a flexible trip is the safer half.

Daylight in September

12.6 hours of daylight, losing 1.5 hours across the month. That is between Eugene's extremes of 15.5 and 8.9 hours, so days are long enough not to constrain the plan.

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. Within September itself the daily swing is 14.1 °C, so mornings and afternoons need different clothes.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

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

September 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, 1 day more rain. Tri-Cities is close enough to be a coin toss — 2 °C warmer, 3 days less rain.

So: September works, with July the better month by 9 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Eugene

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