Viana do Castelo weather in December

In December, Viana do Castelo sees average daytime highs of 13°C and overnight lows near 8°C, with 227 mm of rain across 14.1 wet days and about 9 hours of daylight. It is the 11th-warmest and 3rd-wettest month of the year here.

Day-to-day highs hold fairly steady near 13°C through the month. The sky is clear or mostly clear about 30% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 12 min at the start of December to 9 hours by month's end. Set against the rest of the year, December is Viana do Castelo's 12th-clearest and 2nd-windiest month. For the whole year in context, see Viana do Castelo's year-round climate.

Daytime high
13°
11th warmest
Overnight low
3rd coldest
Rainfall
227 mm
14.1 wet days
Daylight
9 hours
8:02 AM – 5:01 PM
Cloud cover
61%
12th clearest
Wind
13 km/h
2nd windiest
Solar energy
1.59 kWh/m²
Travel score
3.5
out of 10

Viana do Castelo is city seat of Viana do Castelo municipality in northern Portugal and seat of the municipality and district of the same name.

Air quality
Excellent
PM10 9.1 µg/m³ · 2013

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 13°C through the month.

A typical December day in Viana do Castelo reaches about 13°C in the afternoon and slips back to 8°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 11°C and 16°C. Set against its neighbours, December runs about 2°C cooler than November and on par with January.

10°15°20°151015202531
Avg high (°C)Avg low (°C)
1148
2148
3148
4148
5148
6148
7148
8148
9148
10148
11148
12148
13148
14148
15138
16138
17138
18138
19138
20138
21138
22138
23137
24137
25137
26137
27137
28137
29137
30137
31137

Viana do Castelo weather by month

How December compares with the rest of the year at a glance. December is the 11th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan13° / 21813.69.33.3
Feb14° / 14210.410.33.9
Mar15° / 16511.311.74.7
Apr17° / 10°1541313.15.0
May19° / 12°13311.814.35.9
Jun21° / 14°566.9157.2
Jul23° / 16°324.414.78.4
Aug24° / 16°45513.78.3
Sep22° / 15°897.412.37.3
Oct19° / 13°23213.210.95.7
Nov15° / 10°23214.29.64.3
Dec13° / 22714.193.5

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% of the time in December, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 12% of December, with mostly cloudy or overcast conditions the remaining 58%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14357
24357
34258
44159
54159
64159
74159
84159
94159
104159
114159
124258
134258
144159
154258
164258
174456
184456
194357
204456
214357
224357
234357
244258
254159
264159
274159
284060
294060
304060
313961

Chance of precipitation in December

Any precipitation

Viana do Castelo gets around 227 mm of rain over 14.1 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 45% and peaks near 50% on the wettest days.

0%20%40%60%151015202531
Rain chance (%)
145
245
345
445
544
644
744
844
943
1043
1143
1243
1343
1443
1543
1643
1743
1843
1944
2044
2145
2245
2346
2447
2548
2648
2749
2849
2949
3050
3150

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 95% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1946
2946
3946
4946
5946
6946
7946
8946
9946
10955
11955
12955
13955
14955
15955
16955
17955
18955
19955
20955
21955
22955
23955
24955
25955
26955
27955
28955
29955
30955
31955

Wind in December

Winds average 13 km/h in December.

Across December, daily wind ranges from about 13 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
113light breeze
213light breeze
313light breeze
413light breeze
513light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1013light breeze
1113light breeze
1213light breeze
1313light breeze
1413light breeze
1513light breeze
1613light breeze
1713light breeze
1813light breeze
1913light breeze
2014light breeze
2114light breeze
2214light breeze
2314light breeze
2414light breeze
2514light breeze
2614light breeze
2714light breeze
2814light breeze
2914light breeze
3014light breeze
3114light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 12 min at the start of December to 9 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 12 minutes over December. Sunrise moves from 7:49 AM to 8:08 AM, and sunset from 5:01 PM to 5:09 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.27:495:01
29.27:505:01
39.27:515:01
49.17:525:00
59.17:535:00
69.17:545:00
79.17:555:00
89.17:565:00
99.17:575:00
109.07:575:00
119.07:585:00
129.07:595:00
139.08:005:01
149.08:005:01
159.08:015:01
169.08:025:01
179.08:025:01
189.08:035:02
199.08:045:02
209.08:045:03
219.08:055:03
229.08:055:03
239.08:065:04
249.08:065:04
259.08:065:05
269.08:075:06
279.08:075:06
289.08:075:07
299.08:085:07
309.08:085:08
319.08:085:09

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.59 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 1.59 kWh/m² to a high of 7.29 kWh/m² in July across the year — December's 1.59 kWh/m² sits near the bottom.

00.511.522.5151015202531
Solar energy (kWh/m²)Level
11.7Dim
21.7Dim
31.7Dim
41.7Dim
51.7Dim
61.7Dim
71.6Dim
81.6Dim
91.6Dim
101.6Dim
111.6Dim
121.6Dim
131.6Dim
141.6Dim
151.6Dim
161.6Dim
171.6Dim
181.6Dim
191.6Dim
201.6Dim
211.6Dim
221.6Dim
231.6Dim
241.6Dim
251.6Dim
261.6Dim
271.6Dim
281.6Dim
291.6Dim
301.6Dim
311.6Dim
Planning a trip in December

Hazard calendar for Viana do Castelo

In seasonPeak

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

Viana do Castelo's rainy season runs October–May, 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 Viana do Castelo?

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

3.5
Sightseeing
11th-best month of the year
0.0
Beach & pool
11th-best month of the year

December is a weaker month for outdoor sightseeing in Viana do Castelo.

What to pack for Viana do Castelo in December

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

In December, Viana do Castelo sees daytime highs around 13°C and nights near 8°C. Pack rain gear. Worth having: a warm layer. About 14 days see rain.

rain geara warm layer

Sea temperature near Viana do Castelo in December

The nearest coast averages about 15°C in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in August at about 17°C and coldest in February near 13°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

12°14°16°18°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°C)Comfort
Jan14Bracing
Feb13Bracing
Mar14Bracing
Apr14Bracing
May15Cool
Jun17Cool
Jul17Cool
Aug17Cool
Sep17Cool
Oct17Cool
Nov16Cool
Dec15Bracing

UV index in Viana do Castelo in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Viana do Castelo peaks around June 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 23UV 9Dec 20UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7High
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct4Moderate
Nov2Moderate
Dec2Low
Location & terrain

Where is Viana do Castelo?

Viana do Castelo sits at 41.7°N, 8.8°W, 12 m above sea level, in Portugal. The nearest listed city is Esposende, 18 km away.

Topography around Viana do Castelo

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Viana do Castelo.

Within 3 km, the terrain around Viana do Castelo has significant variations in elevation — a maximum elevation change of 300 m around an average of 29 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 793 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,517 m.

The land around Viana do Castelo is covered by water (37%), trees (23%) and artificial surfaces (22%) within 3 km, water (47%) and trees (29%) within 16 km, and trees (38%), water (32%) and grassland (22%) within 80 km.

3 km
300 m
16 km
793 m
80 km
1,517 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwaterwetland
December weather nearby: Esposende 18 km · Ponte de Lima 22 km · Barcelos 25 km · Pedroso 32 km · Póvoa de Varzim 35 km · Braga 38 km · Arcos de Valdevez 38 km · Vila do Conde 38 km

Portugal travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / E / F
230 V · 50 Hz
Prices
≈ 60% of US
price level, 2025
GDP per capita
$32,082
2025
Happiness
6.0 / 10
World Happiness, 2025
Safe drinking water
95%
of population, 2024
Homicide rate
0.7
per 100k, 2022
Road deaths
8.2
per 100k/yr, 2019
Income group
High
World Bank
English
Very high
EF EPI 612
Religion
Catholic 68%not applicable 13%no religion 12%no response 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 Viana do Castelo (41.6932°, -8.8329°, elevation 12 m), 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).