Bethany weather in December

In December, Bethany sees average daytime highs of 46°F and overnight lows near 36°F, with 7.6 in of precipitation across 18 wet days and about 8.6 hours of daylight. It is the 12th-warmest and 1st-wettest month of the year here.

Day-to-day highs hold fairly steady near 46°F through the month. The sky is clear or mostly clear about 12% of the time in December, and the air most often feels dry.

Daylight stretches from about 8 h 48 min at the start of December to 8 h 36 min by month's end. Set against the rest of the year, December is Bethany's 12th-clearest and 1st-windiest month. For the whole year in context, see Bethany's year-round climate.

Daytime high
46°
12th warmest
Overnight low
36°
1st coldest
Precipitation
7.6 in
18 wet days
Daylight
8 h 30 min
7:52 AM – 4:23 PM
Cloud cover
78%
12th clearest
Wind
5 mph
1st windiest
Solar energy
1.02 kWh/m²
Travel score
0.9
out of 10

Bethany is unincorporated community in Washington County, Oregon, United States.

Density
1,550/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 46°F through the month.

A typical December day in Bethany reaches about 46°F in the afternoon and slips back to 36°F overnight — a 10°F spread between the day's warmth and the night's chill. On most days the high lands between 39°F and 52°F. Set against its neighbours, December runs about 6°F cooler than November and on par with January.

20°30°40°50°60°151015202531
Avg high (°F)Avg low (°F)
14737
24737
34737
44737
54637
64636
74636
84636
94636
104636
114636
124636
134636
144636
154636
164636
174636
184536
194536
204536
214536
224536
234536
244536
254536
264536
274536
284536
294536
304536
314536

How December really feels in Bethany

Once humidity and wind are folded in, December averages 0 days that feel above 90°F and 28 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
28
wind chill below the day's low

The story in December is cold — wind chill drags the overnight "feels like" below the raw low.

Bethany weather by month

How December compares with the rest of the year at a glance. December is the 12th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan47° / 36°6.617.31.88.91.2
Feb50° / 37°5.014.81.510.12.0
Mar55° / 39°5.717.50.711.62.8
Apr60° / 42°4.516.1013.24.0
May67° / 48°2.811.1014.75.9
Jun72° / 52°1.77.6015.47.0
Jul80° / 56°0.52.3015.18.0
Aug81° / 56°0.62.6013.97.9
Sep75° / 52°1.66.2012.37.7
Oct63° / 46°4.211.9010.75.2
Nov52° / 40°6.917.30.49.32.2
Dec46° / 36°7.6182.28.60.9

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 12% of the time in December, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 9% of December, with mostly cloudy or overcast conditions the remaining 79%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12773
22575
32575
42476
52476
62377
72278
82179
92179
102080
111882
121882
131882
141882
151783
161783
171783
181783
191783
201981
211981
221981
232080
242080
252278
262278
272278
282278
292278
302377
312377

Chance of precipitation in December

Any precipitationSnow

Bethany gets around 7.6 in of rain and snow over 18 wet days in December, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 59% and peaks near 61% on the wettest days, and about 2 days bring snow.

0%20%40%60%151015202531
Rain chance (%)Snow chance (%)
1584
2584
3584
4585
5595
6595
7595
8595
9595
10595
11606
12606
13616
14616
15617
16617
17617
18608
19608
20598
21599
22589
23589
24579
25579
26569
27569
28569
29569
30579
31579

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

Most of December feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, December lands in the dry band about 100% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)
1100
2100
3100
4100
5100
6100
7100
8100
9100
10100
11100
12100
13100
14100
15100
16100
17100
18100
19100
20100
21100
22100
23100
24100
25100
26100
27100
28100
29100
30100
31100

Wind in December

Winds average 5 mph in December, the windiest month of the year.

Across December, daily wind ranges from about 5 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 8 h 48 min at the start of December to 8 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 12 minutes over December. Sunrise moves from 7:38 AM to 7:58 AM, and sunset from 4:24 PM to 4:31 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
18.87:384:24
28.77:394:24
38.77:404:24
48.77:414:23
58.77:424:23
68.77:434:23
78.67:444:23
88.67:454:23
98.67:464:23
108.67:474:23
118.67:484:23
128.67:494:23
138.67:504:23
148.57:504:23
158.57:514:23
168.57:524:23
178.57:534:24
188.57:534:24
198.57:544:24
208.57:544:25
218.57:554:25
228.57:554:25
238.57:564:26
248.57:564:27
258.57:574:27
268.57:574:28
278.57:574:28
288.57:584:29
298.57:584:30
308.57:584:30
318.67:584:31

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.02 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 1.02 kWh/m² to a high of 6.83 kWh/m² in July across the year — December's 1.02 kWh/m² sits near the bottom.

00.511.52151015202531
Solar energy (kWh/m²)Level
11.1Dim
21.1Dim
31.1Dim
41.1Dim
51.1Dim
61.1Dim
71.0Dim
81.0Dim
91.0Dim
101.0Dim
111.0Dim
121.0Dim
131.0Dim
141.0Dim
151.0Dim
161.0Dim
171.0Dim
181.0Dim
191.0Dim
201.0Dim
211.0Dim
221.0Dim
231.0Dim
241.0Dim
251.0Dim
261.0Dim
271.0Dim
281.0Dim
291.1Dim
301.1Dim
311.1Dim
Planning a trip in December

Hazard calendar for Bethany

In seasonPeak

In December, Bethany sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

Bethany's rainy season runs October–April, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is December a good time to visit Bethany?

Our two travel scores rate December for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

0.9
Sightseeing
12th-best month of the year
0.0
Beach & pool
10th-best month of the year

December is a weaker month for outdoor sightseeing in Bethany.

What to pack for Bethany in December

From December's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In December, Bethany sees daytime highs around 46°F and nights near 36°F. Pack a warm layer and rain gear. Worth having: a heavy coat. About 18 days see rain.

a warm layerrain geara heavy coat

UV index in Bethany in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 1. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Bethany peaks around July 17 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateVery highVery highHighModerateLowJul 17UV 8Dec 15UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr5Moderate
May8Very high
Jun7High
Jul8Very high
Aug7High
Sep4Moderate
Oct3Moderate
Nov1Low
Dec1Low

Air quality in Bethany in December

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where December falls, not just the annual average.

Air quality in Bethany is worst in September — around 22 µg/m³ PM2.5 (moderate), about 3.0× the cleanest month (January, 7 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1621 µg/m³Jan 117 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb9Good
Mar11Good
Apr11Good
May10Good
Jun9Good
Jul8Good
Aug13Moderate
Sep22Moderate
Oct14Moderate
Nov9Good
Dec7Good
Location & terrain

Where is Bethany?

Bethany sits at 45.6°N, 122.9°W, 184 ft above sea level, in United States. The nearest listed city is Aloha, 4.3 mi away.

Topography around Bethany

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Bethany.

Within 2 miles, the terrain around Bethany has only modest variations in elevation — a maximum elevation change of 282 ft around an average of 240 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,555 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,990 ft.

The land around Bethany is covered by trees (43%) and artificial surfaces (31%) within 2 miles, trees (51%) within 10 miles, and trees (78%) within 50 miles.

2 miles
282 ft
10 miles
1,555 ft
50 miles
4,990 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Aloha 4.3 mi · Beaverton 5.6 mi · Hillsboro 6.2 mi · Portland 9.3 mi · Tigard 9.9 mi · Vancouver 11 mi · Forest Grove 12 mi · Hazel Dell 12 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Bethany (45.5579°, -122.8676°, elevation 184 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).