Forest Grove weather in December

In December, Forest Grove sees average daytime highs of 45°F and overnight lows near 36°F, with 8.0 in of precipitation across 17.5 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 45°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 Forest Grove's 12th-clearest and 5th-windiest month. For the whole year in context, see Forest Grove's year-round climate.

Daytime high
45°
12th warmest
Overnight low
36°
1st coldest
Precipitation
8.0 in
17.5 wet days
Daylight
8 h 30 min
7:53 AM – 4:24 PM
Cloud cover
78%
12th clearest
Wind
5 mph
5th windiest
Solar energy
1.03 kWh/m²
Travel score
0.8
out of 10

Forest Grove is city in Oregon, USA.

Density
1,608/km²
people per km²
Founded
1840

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 45°F through the month.

A typical December day in Forest Grove reaches about 45°F in the afternoon and slips back to 36°F overnight — a 9°F spread between the day's warmth and the night's chill. On most days the high lands between 38°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)
14637
24637
34637
44636
54636
64636
74636
84536
94536
104536
114536
124536
134536
144536
154536
164536
174536
184536
194536
204536
214536
224436
234436
244436
254436
264435
274435
284435
294435
304435
314435

How December really feels in Forest Grove

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.

Forest Grove 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
Jan46° / 36°6.817.11.98.91.0
Feb49° / 37°5.214.21.610.11.8
Mar54° / 39°5.917.30.911.62.7
Apr59° / 42°4.515.60.113.23.8
May66° / 47°2.710.6014.75.9
Jun72° / 52°1.67.2015.47.1
Jul80° / 56°0.42.2015.18.2
Aug80° / 57°0.52.5013.98.1
Sep74° / 53°1.76012.37.7
Oct62° / 46°4.211.5010.75.1
Nov51° / 40°7.017.30.59.32.0
Dec45° / 36°8.017.52.38.60.8

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 8% of December, with mostly cloudy or overcast conditions the remaining 80%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12575
22575
32476
42377
52377
62278
72278
82080
92080
101981
111882
121783
131783
141783
151783
161783
171783
181783
191783
201882
211882
221882
231882
242080
252080
262179
272179
282179
292278
302377
312377

Chance of precipitation in December

Any precipitationSnow

Forest Grove gets around 8.0 in of rain and snow over 17.5 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 57% and peaks near 60% on the wettest days, and about 2 days bring snow.

0%20%40%60%151015202531
Rain chance (%)Snow chance (%)
1575
2575
3575
4575
5575
6575
7585
8585
9586
10586
11586
12596
13596
14597
15607
16607
17598
18598
19598
20589
21579
22579
23569
24569
25559
26559
27559
28559
29559
30559
31559

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.

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

0246810151015202531
Wind speed (mph)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
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 7:39 AM to 7:59 AM, and sunset from 4:25 PM to 4:32 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
18.87:394:25
28.77:404:25
38.77:414:25
48.77:424:24
58.77:434:24
68.77:444:24
78.67:454:24
88.67:464:24
98.67:474:24
108.67:484:24
118.67:494:24
128.67:504:24
138.67:514:24
148.57:514:24
158.57:524:24
168.57:534:24
178.57:534:25
188.57:544:25
198.57:554:25
208.57:554:26
218.57:564:26
228.57:564:27
238.57:574:27
248.57:574:28
258.57:574:28
268.57:584:29
278.57:584:29
288.57:584:30
298.57:594:31
308.57:594:32
318.67:594:32

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.03 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 1.03 kWh/m² to a high of 6.77 kWh/m² in July across the year — December's 1.03 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
281.1Dim
291.1Dim
301.1Dim
311.1Dim
Planning a trip in December

Hazard calendar for Forest Grove

In seasonPeak

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

Forest Grove'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 Forest Grove?

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

0.8
Sightseeing
12th-best month of the year
0.0
Beach & pool
9th-best month of the year

December is a weaker month for outdoor sightseeing in Forest Grove.

What to pack for Forest Grove in December

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

In December, Forest Grove sees daytime highs around 45°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

Sea temperature near Forest Grove in December

The nearest coast averages about 50°F in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 38 mi away) is warmest in August at about 59°F and coldest in February near 49°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

50°55°60°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°F)Comfort
Jan50Bracing
Feb49Bracing
Mar50Bracing
Apr51Bracing
May54Bracing
Jun57Bracing
Jul58Bracing
Aug59Bracing
Sep58Bracing
Oct55Bracing
Nov53Bracing
Dec50Bracing

UV index in Forest Grove 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 Forest Grove peaks around July 17 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 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 17UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr5High
May8Very high
Jun7High
Jul8Very high
Aug7High
Sep5Moderate
Oct3Moderate
Nov1Low
Dec1Low

Air quality in Forest Grove 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 Forest Grove 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 Forest Grove?

Forest Grove sits at 45.5°N, 123.1°W, 203 ft above sea level, in United States. The nearest listed city is Hillsboro, 5.6 mi away.

Topography around Forest Grove

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

Within 2 miles, the terrain around Forest Grove has only modest variations in elevation — a maximum elevation change of 331 ft around an average of 187 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,303 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,245 ft.

The land around Forest Grove is covered by trees (33%), grassland (24%) and cropland (24%) within 2 miles, trees (56%) and cropland (20%) within 10 miles, and trees (72%) within 50 miles.

2 miles
331 ft
10 miles
2,303 ft
50 miles
4,245 ft
treesgrasslandcroplandartificial surfaceswater
December weather nearby: Hillsboro 5.6 mi · Aloha 12 mi · Bethany 12 mi · Beaverton 15 mi · Newberg 17 mi · Sherwood 17 mi · Tigard 17 mi · Tualatin 19 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 Forest Grove (45.5198°, -123.1107°, elevation 203 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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).