Swellendam weather in December

In December, Swellendam sees average daytime highs of 27°C and overnight lows near 15°C, with 29 mm of rain across 5.4 wet days and about 14.2 hours of daylight. It is the 3rd-warmest and 9th-wettest month of the year here.

Day-to-day highs hold fairly steady near 27°C through the month. The sky is clear or mostly clear about 51% of the time in December, and the air most often feels dry.

Daylight stretches from about 14 h 06 min at the start of December to 14 h 12 min by month's end. Set against the rest of the year, December is Swellendam's 6th-clearest and 1st-windiest month. For the whole year in context, see Swellendam's year-round climate.

Daytime high
27°
3rd warmest
Overnight low
15°
10th coldest
Rainfall
29 mm
5.4 wet days
Daylight
14 h 18 min
5:27 AM – 7:42 PM
Cloud cover
42%
6th clearest
Wind
11 km/h
1st windiest
Solar energy
7.53 kWh/m²
Travel score
7.4
out of 10

Swellendam is town in Western Cape, South Africa.

Founded
1746

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 27°C through the month.

A typical December day in Swellendam reaches about 27°C in the afternoon and slips back to 15°C overnight — a 12°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 32°C. Set against its neighbours, December runs about 2°C warmer than November and about 1°C cooler than January.

10°15°20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12614
22614
32614
42714
52714
62714
72715
82715
92715
102715
112715
122715
132715
142715
152715
162715
172715
182715
192815
202815
212815
222815
232815
242816
252816
262816
272816
282816
292816
302816
312816

Swellendam weather by month

How December compares with the rest of the year at a glance. December is the 3rd-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 16°285.1147.0
Feb28° / 16°235.313.37.0
Mar27° / 15°35612.37.5
Apr24° / 12°376.111.27.7
May21° / 305.410.37.5
Jun18° / 316.19.86.9
Jul18° / 336106.8
Aug19° / 336.510.76.9
Sep21° / 245.711.87.3
Oct23° / 11°395.512.97.8
Nov25° / 13°405.813.87.7
Dec27° / 15°295.414.27.4

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 51% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 16% of December, with mostly cloudy or overcast conditions the remaining 32%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16733
26733
36733
46733
56733
66634
76634
86634
96634
106634
116634
126634
136733
146733
156733
166733
176733
186733
196733
206832
216931
226931
236931
247030
257030
267129
277129
287129
297129
307228
317228

Chance of precipitation in December

Any precipitation

Swellendam gets around 29 mm of rain over 5.4 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 18% and peaks near 19% on the wettest days.

0%10%20%30%151015202531
Rain chance (%)
116
216
316
416
516
616
716
816
916
1016
1116
1216
1316
1417
1517
1618
1718
1819
1919
2019
2119
2219
2319
2419
2519
2619
2719
2819
2919
3019
3119

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 58% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
174224
273234
372244
470255
568275
667276
766286
864297
964297
1062308
1162308
1260319
1360319
14593110
15593110
16583111
17583111
18563212
19563212
20563212
21553213
22543313
23533314
24523414
25513415
26503515
27493516
28473617
29463617
30453718
31453718

Wind in December

Winds average 11 km/h in December, the windiest month of the year.

Across December, daily wind ranges from about 11 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
111calm
211calm
311calm
411calm
511calm
611calm
711calm
811calm
911calm
1011calm
1111calm
1211calm
1311calm
1411calm
1511calm
1611calm
1711calm
1811calm
1911calm
2011calm
2111calm
2211calm
2311calm
2411calm
2511calm
2611calm
2711calm
2811calm
2911calm
3011calm
3111calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 14 h 06 min at the start of December to 14 h 12 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 6 minutes over December. Sunrise moves from 5:25 AM to 5:34 AM, and sunset from 7:31 PM to 7:49 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.15:257:31
214.15:257:32
314.15:257:33
414.15:257:34
514.25:257:34
614.25:257:35
714.25:257:36
814.25:257:37
914.25:257:37
1014.25:257:38
1114.25:257:39
1214.25:267:39
1314.25:267:40
1414.25:267:41
1514.35:267:41
1614.35:277:42
1714.35:277:43
1814.35:277:43
1914.35:287:44
2014.35:287:44
2114.35:297:45
2214.35:297:45
2314.35:307:46
2414.35:307:46
2514.35:317:47
2614.35:317:47
2714.35:327:47
2814.35:327:48
2914.35:337:48
3014.25:347:48
3114.25:347:49

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 7.53 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 2.64 kWh/m² to a high of 7.53 kWh/m² in December across the year — December's 7.53 kWh/m² sits near the top of that range.

02468151015202531
Solar energy (kWh/m²)Level
17.5Intense
27.5Intense
37.5Intense
47.5Intense
57.5Intense
67.5Intense
77.5Intense
87.5Intense
97.5Intense
107.5Intense
117.5Intense
127.5Intense
137.5Intense
147.6Intense
157.6Intense
167.6Intense
177.6Intense
187.6Intense
197.6Intense
207.6Intense
217.6Intense
227.6Intense
237.6Intense
247.6Intense
257.6Intense
267.6Intense
277.6Intense
287.6Intense
297.6Intense
307.6Intense
317.6Intense
Planning a trip in December

Is December a good time to visit Swellendam?

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

7.4
Sightseeing
6th-best month of the year
7.6
Beach & pool
3rd-best month of the year

December is one of the better times to visit Swellendam for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Swellendam in December

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

In December, Swellendam sees daytime highs around 27°C and nights near 15°C. Pack light clothes and sun protection. About 5 days see rain.

light clothessun protection

Sea temperature near Swellendam in December

The nearest coast averages about 20°C 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 56 km away) is warmest in February at about 22°C and coldest in July near 15°C.

It's comfortable for a long swim from Dec 15 to Mar 26 — about 3.4 months when the water holds above 20°C.

15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingcomfortable to swim
Sea temperature (°C)Comfort
Jan21Refreshing
Feb22Refreshing
Mar21Refreshing
Apr19Cool
May17Cool
Jun16Cool
Jul15Cool
Aug15Cool
Sep16Cool
Oct17Cool
Nov19Cool
Dec20Refreshing

UV index in Swellendam in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Swellendam peaks around January 13 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 20 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highModerateExtremeJan 13UV 13Jun 20UV 3
UV index (midday)Level
Jan14Extreme
Feb10Very high
Mar10Very high
Apr6High
May4Moderate
Jun3Moderate
Jul3Moderate
Aug4Moderate
Sep6High
Oct10Extreme
Nov12Extreme
Dec12Extreme

Air quality in Swellendam 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 Swellendam is worst in June — around 17 µg/m³ PM2.5 (moderate), about 2.9× the cleanest month (January, 6 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJun 2017 µg/m³Jan 166 µg/m³
PM2.5 (µg/m³)Level
Jan6Good
Feb8Good
Mar9Good
Apr10Good
May16Moderate
Jun17Moderate
Jul17Moderate
Aug16Moderate
Sep13Moderate
Oct9Good
Nov7Good
Dec8Good
Location & terrain

Where is Swellendam?

Swellendam sits at 34.0°S, 20.4°E, 128 m above sea level, in South Africa. The nearest listed city is Montagu, 40 km away.

Topography around Swellendam

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

Within 3 km, the terrain around Swellendam has only modest variations in elevation — a maximum elevation change of 248 m around an average of 163 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,677 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,683 m.

The land around Swellendam is covered by trees (28%), grassland (25%) and shrubs (24%) within 3 km, grassland (33%), cropland (31%) and shrubs (24%) within 16 km, and grassland (38%), shrubs (27%) and cropland (22%) within 80 km.

3 km
248 m
16 km
1,677 m
80 km
1,683 m
treesshrubsgrasslandcroplandartificial surfaceswater
December weather nearby: Montagu 40 km · Ashton 41 km · Robertson 57 km · Bredasdorp 68 km · Riversdale 76 km · Caledon 96 km · Worcester 101 km · Gansbaai 118 km

South Africa travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / M / N
230 V · 50 Hz
Prices
≈ 41% of US
price level, 2025
GDP per capita
$6,598
2025
Happiness
5.0 / 10
World Happiness, 2025
Safe drinking water
68%
of population, 2024
Homicide rate
43.7
per 100k, 2022
Road deaths
22.2
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Very high
EF EPI 602
Religion
Christian 86%or other traditional African religions 5%nothing in particular 5%Muslim 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 Swellendam (-34.0226°, 20.4417°, elevation 128 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. 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).