Climate averages 1991–2020

Beaverton weather
in December.

A cold, very wet month: the coolest and the wettest of the year.

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

Average high 7.3°C Daytime mean, December
Average low 1.5°C Night-time mean, December
Rainfall 193 mm 18 days with ≥1 mm
Daylight 9 h Sunrise to sunset, per day
Every month in Beaverton · average highYear overview

December is a cold month in Beaverton: daytime highs average 7.3°C and nights cool to about 1.5°C. By daytime temperature it is the coolest month of the year.

Expect about 193 mm of rain on roughly 18 days, which makes December a very wet month (the wettest month of the year). Daylight, from sunrise to sunset, lasts about 8 h 47 min on an average December day.

The nearest other city in this atlas is Portland (11 km away). In December its highs average 7.7°C, about as warm as Beaverton, with 193 mm of rain.

Among the 498 cities listed in the United States, Beaverton ranks joint 293rd of 498 for the warmest December highs and joint 487th of 498 for the driest December (rainfall, lowest first). The mean December high of those 498 cities is 10.5°C; Beaverton is 3.2°C cooler than that mean.

From December to January, average highs rise by 0.6°C to 7.9°C, and monthly rainfall falls from 193 mm to 167 mm.

The annual picture

December 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 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, selected 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

December 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.