Swansea weather in December

In December, Swansea sees average daytime highs of 9°C and overnight lows near 6°C, with 145 mm of precipitation across 16.8 wet days and about 7.7 hours of daylight. It is the 10th-warmest and 1st-wettest month of the year here.

Day-to-day highs hold fairly steady near 9°C through the month. The sky is clear or mostly clear about 14% of the time in December, and the air most often feels dry.

Daylight stretches from about 7 h 54 min at the start of December to 7 h 36 min by month's end. Set against the rest of the year, December is Swansea's 10th-clearest and 1st-windiest month. For the whole year in context, see Swansea's year-round climate.

Daytime high
10th warmest
Overnight low
4th coldest
Precipitation
145 mm
16.8 wet days
Daylight
7 h 36 min
8:24 AM – 4:00 PM
Cloud cover
73%
10th clearest
Wind
26 km/h
1st windiest
Solar energy
0.65 kWh/m²
Travel score
1.4
out of 10

Swansea is city in Wales.

Air quality
Good
PM2.5 9.9 µg/m³ · 2019
Founded
1158

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 9°C through the month.

A typical December day in Swansea reaches about 9°C in the afternoon and slips back to 6°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 5°C and 12°C. Set against its neighbours, December runs about 2°C cooler than November and about 1°C warmer than January.

10°15°151015202531
Avg high (°C)Avg low (°C)
1107
2107
3107
4107
597
697
797
896
996
1096
1196
1296
1396
1496
1596
1696
1796
1896
1996
2096
2196
2296
2386
2486
2586
2686
2786
2886
2986
3086
3186

Swansea weather by month

How December compares with the rest of the year at a glance. December is the 10th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 128170.48.11.1
Feb / 90130.69.61.1
Mar / 8313.70.311.51.6
Apr11° / 69120.113.62.5
May13° / 10°7212.4015.33.6
Jun16° / 12°7912.2016.34.6
Jul18° / 14°8613.8015.95.2
Aug18° / 15°10114.3014.45.2
Sep17° / 13°9613.2012.44.8
Oct14° / 11°14316.7010.43.4
Nov11° / 14317.308.62.2
Dec / 14516.80.37.71.4

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 14% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 13% of December, with mostly cloudy or overcast conditions the remaining 73%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13268
23268
33268
43268
53169
63169
73169
83070
92971
102971
112872
122773
132773
142674
152575
162575
172575
182575
192575
202575
212575
222575
232575
242575
252575
262575
272575
282575
292575
302674
312674

Chance of precipitation in December

Any precipitation

Swansea gets around 145 mm of rain and snow over 16.8 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 54% and peaks near 56% on the wettest days, and about 0 day brings snow.

0%20%40%60%151015202531
Rain chance (%)
154
254
353
453
553
653
752
852
952
1052
1153
1253
1353
1453
1554
1654
1754
1855
1955
2055
2156
2256
2356
2456
2555
2655
2755
2855
2955
3055
3155

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 26 km/h in December, the windiest month of the year.

Across December, daily wind ranges from about 25 km/h on the calmest days to 26 km/h at its breeziest. It stays fairly steady from day to day.

0102030151015202531
Wind speed (km/h)Feels
125breezy
225breezy
326breezy
426breezy
526breezy
626breezy
726breezy
826breezy
926breezy
1026breezy
1126breezy
1226breezy
1326breezy
1426breezy
1526breezy
1626breezy
1726breezy
1826breezy
1926breezy
2026breezy
2126breezy
2226breezy
2326breezy
2426breezy
2526breezy
2626breezy
2726breezy
2826breezy
2926breezy
3026breezy
3126breezy

Sunrise & sunset in December

DaylightNight

Daylight runs from about 7 h 54 min at the start of December to 7 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 18 minutes over December. Sunrise moves from 8:08 AM to 8:30 AM, and sunset from 4:03 PM to 4:08 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
17.98:084:03
27.98:094:03
37.98:104:02
47.88:124:02
57.88:134:01
67.88:144:01
77.88:154:01
87.78:164:00
97.78:174:00
107.78:184:00
117.78:194:00
127.78:204:00
137.68:214:00
147.68:224:00
157.68:234:00
167.68:244:00
177.68:254:00
187.68:254:00
197.68:264:01
207.68:264:01
217.68:274:02
227.68:284:02
237.68:284:02
247.68:284:03
257.68:294:04
267.68:294:04
277.68:294:05
287.68:294:06
297.68:304:06
307.68:304:07
317.68:304:08

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 0.65 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 0.65 kWh/m² to a high of 5.63 kWh/m² in June across the year — December's 0.65 kWh/m² sits near the bottom.

00.511.52151015202531
Solar energy (kWh/m²)Level
10.8Dim
20.8Dim
30.7Dim
40.7Dim
50.7Dim
60.7Dim
70.7Dim
80.7Dim
90.7Dim
100.7Dim
110.7Dim
120.7Dim
130.7Dim
140.7Dim
150.6Dim
160.6Dim
170.6Dim
180.6Dim
190.6Dim
200.6Dim
210.6Dim
220.6Dim
230.6Dim
240.6Dim
250.6Dim
260.6Dim
270.6Dim
280.6Dim
290.6Dim
300.6Dim
310.7Dim
Planning a trip in December

Is December a good time to visit Swansea?

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

1.4
Sightseeing
10th-best month of the year
0.0
Beach & pool
7th-best month of the year

December is a weaker month for outdoor sightseeing in Swansea.

What to pack for Swansea in December

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

In December, Swansea sees daytime highs around 9°C and nights near 6°C. Pack a warm layer and rain gear. Worth having: a windbreaker. About 17 days see rain.

a warm layerrain geara windbreaker

Sea temperature near Swansea in December

The nearest coast averages about 10°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 18°C and coldest in February near 8°C.

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

5°10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan8Bracing
Feb8Bracing
Mar8Bracing
Apr9Bracing
May11Bracing
Jun14Bracing
Jul16Cool
Aug18Cool
Sep17Cool
Oct15Cool
Nov12Bracing
Dec10Bracing

UV index in Swansea 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 Swansea peaks around August 13 at about 6 (high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near January 1 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 6 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowAug 13UV 6Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May6High
Jun6High
Jul6High
Aug7High
Sep4Moderate
Oct2Moderate
Nov1Low
Dec1Low
Location & terrain

Where is Swansea?

Swansea sits at 51.6°N, 3.9°W, 18 m above sea level, in United Kingdom. The nearest listed city is Clydach, 8.0 km away.

Topography around Swansea

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

Within 3 km, the terrain around Swansea has only modest variations in elevation — a maximum elevation change of 194 m around an average of 44 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 422 m; within 80 km, large variations in elevation — a maximum elevation change of 878 m.

The land around Swansea is covered by artificial surfaces (34%), water (32%) and trees (23%) within 3 km, water (35%), grassland (28%) and trees (26%) within 16 km, and grassland (46%) and water (35%) within 80 km.

3 km
194 m
16 km
422 m
80 km
878 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
December weather nearby: Clydach 8.0 km · Briton Ferry 9.0 km · Gorseinon 9.0 km · Neath 11 km · Llanelli 17 km · Ammanford 19 km · Maesteg 20 km · Porthcawl 23 km

United Kingdom travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type D / G / M
230 V · 50 Hz
Prices
≈ 89% of US
price level, 2025
GDP per capita
$57,602
2025
Happiness
6.7 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
1.1
per 100k, 2021
Road deaths
3.2
per 100k/yr, 2019
Income group
High
World Bank
Religion
Christian 60%none 26%Muslim 4%other 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 Swansea (51.6208°, -3.9432°, elevation 18 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).