Climate averages 1991–2020

Beaverton weather
in September.

A warm, moderately wet month: the 3rd warmest and the 3rd driest of the year. Meets the pleasant-weather rule

Long-term climate patterns, not a forecast for a particular trip.

Average high 23.7°C Daytime mean, September
Average low 12.0°C Night-time mean, September
Rainfall 42 mm 6 days with ≥1 mm
Daylight 13 h Sunrise to sunset, per day
Every month in Beaverton · average highYear overview

September is a warm month in Beaverton: daytime highs average 23.7°C and nights cool to about 12.0°C. By daytime temperature it is the 3rd warmest of the 12 months.

Expect about 42 mm of rain on roughly 6 days, which makes September a moderately wet month (the 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 35 min on an average September day.

The nearest other city in this atlas is Portland (11 km away). In September its highs average 24.1°C, about as warm as Beaverton, with 42 mm of rain.

Among the 498 cities listed in the United States, Beaverton ranks joint 374th of 498 for the warmest September highs and joint 166th of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Beaverton is 3.2°C cooler than that mean.

From September to October, average highs fall by 7.1°C to 16.6°C, and monthly rainfall rises from 42 mm to 106 mm.

The annual picture

September in context

30-year average
Average highAverage low°C
Average daily high and low temperatures by month The same values are available in the monthly table below. Lines show mean daily maxima and minima, not a forecast interval. -5051015202530 JanFebMarAprMayJunJulAugSepOctNovDec

Monthly rainfall

Average total · mm
Average monthly rainfall totalsEach bar is a mean monthly total over 1991–2020. Full numbers are in the table. JanFebMarAprMayJunJulAugSepOctNovDec 2000

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Beaverton climate table

1991–2020
Monthly climate averages for Beaverton, 1991–2020
MonthAverage highHigh / lowAverage lowRainfall mm/monthRain days ≥1 mm/dayDaylight hours/dayDay­light h/day
January 7.9°C1.6°C1.6°C16717.39.19 h
February 9.6°C1.8°C1.8°C13015.010.310 h
March 12.0°C3.3°C3.3°C14517.511.912 h
April 14.4°C5.1°C5.1°C11516.113.513 h
May 18.5°C8.3°C8.3°C7011.114.915 h
June 21.4°C10.9°C10.9°C437.615.616 h
July 26.6°C13.7°C13.7°C122.315.315 h
August 27.1°C14.2°C14.2°C142.614.114 h
September, selected 23.7°C12.0°C12.0°C426.212.613 h
October 16.6°C7.9°C7.9°C10611.811.011 h
November 10.7°C4.0°C4.0°C17417.39.610 h
December 7.3°C1.5°C1.5°C19318.08.89 h

Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

September in nearby cities

Distance from Beaverton

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Beaverton) is explained once on the Beaverton year overview and on the Sources, method and limits page.

Portland lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.