Swellendam weather in May

In May, Swellendam sees average daytime highs of 21°C and overnight lows near 9°C, with 30 mm of rain across 5.4 wet days and about 10.3 hours of daylight. It is the 8th-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 22°C in the first days to 20°C by the end. The sky is clear or mostly clear about 45% of the time in May, and the air most often feels dry.

Daylight stretches from about 10 h 42 min at the start of May to 9 h 54 min by month's end. Set against the rest of the year, May is Swellendam's 9th-clearest and 12th-windiest month. For the whole year in context, see Swellendam's year-round climate.

Daytime high
21°
8th warmest
Overnight low
5th coldest
Rainfall
30 mm
5.4 wet days
Daylight
10 h 12 min
7:27 AM – 5:42 PM
Cloud cover
45%
9th clearest
Wind
8 km/h
12th windiest
Solar energy
3.08 kWh/m²
Travel score
7.5
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 May

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 22°C in the first days to 20°C by the end.

A typical May day in Swellendam reaches about 21°C in the afternoon and slips back to 9°C overnight — a 12°C spread between the day's warmth and the night's chill. On most days the high lands between 16°C and 27°C. Set against its neighbours, May runs about 3°C cooler than April and about 3°C warmer than June.

10°20°30°151015202531
Avg high (°C)Avg low (°C)
12211
22210
32210
42210
52210
62210
72210
82210
92210
102210
112210
122210
132210
142210
152210
162210
17229
18229
19219
20219
21219
22219
23219
24219
25208
26208
27208
28208
29208
30208
31198

Swellendam weather by month

How May compares with the rest of the year at a glance. May is the 8th-warmest and 8th-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 May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 45% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 19% of May, with mostly cloudy or overcast conditions the remaining 35%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16436
26535
36634
46634
56733
66733
76733
86832
96832
106733
116733
126733
136733
146634
156634
166535
176436
186436
196436
206337
216337
226238
236238
246238
256238
266337
276337
286337
296436
306535
316535

Chance of precipitation in May

Any precipitation

Swellendam gets around 30 mm of rain over 5.4 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 17% and peaks near 22% on the wettest days.

0%10%20%30%151015202531
Rain chance (%)
119
219
318
418
517
617
716
816
915
1015
1115
1215
1314
1414
1514
1615
1715
1816
1916
2017
2117
2218
2319
2419
2520
2620
2721
2821
2922
3022
3122

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the dry band about 96% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
19010
2919
3928
4928
5937
6946
7946
8955
9955
10955
11964
12964
13973
14973
15973
16982
17982
18982
19982
20982
21982
22982
23991
24991
25991
26991
27991
28991
291000
301000
311000

Wind in May

Winds average 8 km/h in May, the calmest month.

Across May, daily wind ranges from about 8 km/h on the calmest days to 8 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
298calm
308calm
318calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 10 h 42 min at the start of May to 9 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 48 minutes over May. Sunrise moves from 7:16 AM to 7:38 AM, and sunset from 5:55 PM to 5:33 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
110.77:165:55
210.67:165:54
310.67:175:53
410.67:185:52
510.57:195:51
610.57:205:50
710.57:205:49
810.57:215:48
910.47:225:47
1010.47:235:46
1110.47:245:46
1210.37:245:45
1310.37:255:44
1410.37:265:43
1510.37:275:42
1610.27:275:42
1710.27:285:41
1810.27:295:40
1910.27:305:39
2010.17:305:39
2110.17:315:38
2210.17:325:38
2310.17:335:37
2410.17:335:36
2510.07:345:36
2610.07:355:35
2710.07:355:35
2810.07:365:34
2910.07:375:34
309.97:375:34
319.97:385:33

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 3.08 kWh/m².

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 — May's 3.08 kWh/m² sits near the bottom.

01234151015202531
Solar energy (kWh/m²)Level
13.5Moderate
23.5Moderate
33.5Moderate
43.4Moderate
53.4Moderate
63.4Moderate
73.4Moderate
83.3Moderate
93.3Moderate
103.3Moderate
113.3Moderate
123.2Moderate
133.2Moderate
143.2Moderate
153.1Moderate
163.1Moderate
173.1Moderate
183.0Moderate
193.0Moderate
203.0Moderate
212.9Moderate
222.9Moderate
232.9Moderate
242.9Moderate
252.8Moderate
262.8Moderate
272.8Moderate
282.8Moderate
292.8Moderate
302.7Moderate
312.7Moderate
Planning a trip in May

Is May a good time to visit Swellendam?

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

7.5
Sightseeing
4th-best month of the year
4.8
Beach & pool
8th-best month of the year

May is one of the better times to visit Swellendam for general sightseeing.

What to pack for Swellendam in May

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

In May, Swellendam sees daytime highs around 21°C and nights near 9°C. Little to plan around — just the basics. About 5 days see rain.

Sea temperature near Swellendam in May

The nearest coast averages about 17°C in May — 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 May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 4 — enough to warrant sun protection. 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 May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May 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
May 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).