Aalst weather in May

In May, Aalst sees average daytime highs of 18°C and overnight lows near 9°C, with 60 mm of rain across 11.9 wet days and about 15.3 hours of daylight. It is the 5th-warmest and 7th-wettest month of the year here.

Highs climb over the month, from about 16°C in the first days to 19°C by the end. The sky is clear or mostly clear about 17% of the time in May, and the air most often feels dry.

Daylight stretches from about 14 h 30 min at the start of May to 15 h 54 min by month's end. Set against the rest of the year, May is Aalst's 5th-clearest and 8th-windiest month. For the whole year in context, see Aalst's year-round climate.

Daytime high
18°
5th warmest
Overnight low
8th coldest
Rainfall
60 mm
11.9 wet days
Daylight
15 h 18 min
5:01 AM – 8:19 PM
Cloud cover
68%
5th clearest
Wind
13 km/h
8th windiest
Solar energy
5.08 kWh/m²
Travel score
5.3
out of 10

Aalst is city in East Flanders, Belgium.

Density
992/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 16°C in the first days to 19°C by the end.

A typical May day in Aalst reaches about 18°C in the afternoon and slips back to 9°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 13°C and 24°C. Set against its neighbours, May runs about 4°C warmer than April and about 3°C cooler than June.

10°20°30°151015202531
Avg high (°C)Avg low (°C)
1168
2168
3168
4178
5178
6178
7178
8179
9179
10179
11179
12179
13179
14189
15189
16189
17189
181810
191810
201810
211810
221810
231910
241910
251910
261910
271911
281911
291911
301911
311911

How May really feels in Aalst

Once humidity and wind are folded in, May averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

May sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Aalst weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 6211.918.20.5
Feb / 54111.39.70.8
Mar10° / 5311.20.811.52.4
Apr14° / 4811.9013.53.9
May18° / 6011.9015.35.3
Jun20° / 12°6311.1016.26.0
Jul23° / 14°7012.3015.86.3
Aug22° / 14°7412014.36.3
Sep19° / 12°5510.9012.45.8
Oct15° / 5811.2010.44.2
Nov10° / 6211.70.38.72.0
Dec / 7112.81.17.80.7

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 17% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 15% of May, with mostly cloudy or overcast conditions the remaining 69%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13070
23070
33070
43070
53169
63169
73268
83268
93367
103367
113367
123268
133169
143169
153169
163169
173169
183268
193268
203268
213268
223268
233268
243268
253268
263169
273169
283169
293367
303367
313268

Chance of precipitation in May

Any precipitation

Aalst gets around 60 mm of rain over 11.9 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 39% and peaks near 41% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
141
240
340
439
539
638
738
837
937
1037
1137
1238
1338
1438
1539
1639
1739
1839
1939
2040
2140
2240
2340
2440
2540
2640
2740
2840
2940
3040
3141

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 90% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
19820
29820
39730
49730
59640
69640
79550
89550
99460
109460
119460
129370
139370
149370
159280
169280
179280
189091
199091
2089101
2189101
2287112
2386122
2486122
2584133
2683143
2781154
2881154
2980164
3078175
3177185

Wind in May

Winds average 13 km/h in May.

Across May, daily wind ranges from about 12 km/h on the calmest days to 13 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
2013light breeze
2113light breeze
2213light breeze
2313light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2812light breeze
2912light breeze
3012light breeze
3112light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 14 h 30 min at the start of May to 15 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 84 minutes over May. Sunrise moves from 5:27 AM to 4:44 AM, and sunset from 7:55 PM to 8:39 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.55:277:55
214.55:257:57
314.65:237:59
414.75:218:00
514.75:198:02
614.85:188:03
714.85:168:05
814.95:148:07
914.95:128:08
1015.05:118:10
1115.05:098:11
1215.15:078:13
1315.15:068:14
1415.25:048:16
1515.25:038:17
1615.35:018:19
1715.35:008:20
1815.44:598:22
1915.44:578:23
2015.54:568:25
2115.54:558:26
2215.64:538:27
2315.64:528:29
2415.74:518:30
2515.74:508:31
2615.74:498:33
2715.84:488:34
2815.84:478:35
2915.84:468:36
3015.94:458:38
3115.94:448:39

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.08 kWh/m².

For context, solar energy here swings from a low near 0.64 kWh/m² to a high of 5.34 kWh/m² in June across the year — May's 5.08 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.8Bright
44.8Bright
54.8Bright
64.8Bright
74.8Bright
84.9Bright
94.9Bright
104.9Bright
115.0Bright
125.0Bright
135.0Bright
145.0Bright
155.0Bright
165.1Bright
175.1Bright
185.1Bright
195.2Bright
205.2Bright
215.2Bright
225.2Bright
235.2Bright
245.2Bright
255.2Bright
265.3Bright
275.3Bright
285.3Bright
295.3Bright
305.3Bright
315.3Bright
Planning a trip in May

Is May a good time to visit Aalst?

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

5.3
Sightseeing
5th-best month of the year
1.7
Beach & pool
5th-best month of the year

May is a reasonable time to visit Aalst for sightseeing.

What to pack for Aalst in May

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

In May, Aalst sees daytime highs around 18°C and nights near 9°C. Worth packing: rain gear and sun protection. About 12 days see rain.

rain gearsun protection

Sea temperature near Aalst in May

The nearest coast averages about 12°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 67 km away) is warmest in August at about 19°C and coldest in February near 6°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
Jan6Bracing
Feb6Bracing
Mar6Bracing
Apr9Bracing
May12Bracing
Jun16Cool
Jul18Cool
Aug19Cool
Sep18Cool
Oct15Bracing
Nov11Bracing
Dec8Bracing

UV index in Aalst in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Aalst peaks around June 23 at about 6 (high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 22 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJun 23UV 6Dec 22UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May6High
Jun6High
Jul6High
Aug6High
Sep4Moderate
Oct2Moderate
Nov1Low
Dec1Low

Air quality in Aalst 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 Aalst is worst in April — around 17 µg/m³ PM2.5 (moderate), and holds fairly steady the rest of the year.

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

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodApr 1317 µg/m³Dec 1511 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb13Moderate
Mar17Moderate
Apr17Moderate
May16Moderate
Jun15Moderate
Jul13Moderate
Aug15Moderate
Sep14Moderate
Oct12Moderate
Nov12Good
Dec11Good
Location & terrain

Where is Aalst?

Aalst sits at 50.9°N, 4.0°E, 12 m above sea level, in Belgium. The nearest listed city is Haaltert, 4.0 km away.

Topography around Aalst

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

Within 3 km, the terrain around Aalst has only modest variations in elevation — a maximum elevation change of 34 m around an average of 16 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 116 m; within 80 km, significant variations in elevation — a maximum elevation change of 406 m.

The land around Aalst is covered by artificial surfaces (39%), trees (30%) and grassland (22%) within 3 km, grassland (35%), trees (24%) and cropland (24%) within 16 km, and cropland (37%), grassland (23%) and trees (22%) within 80 km.

3 km
34 m
16 km
116 m
80 km
406 m
treesgrasslandcroplandartificial surfaceswater
May weather nearby: Haaltert 4.0 km · Lede 5.0 km · Denderleeuw 6.0 km · Lebbeke 10 km · Dendermonde 11 km · Herzele 12 km · Asse 12 km · Ninove 12 km

Belgium travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / E
230 V · 50 Hz
Prices
≈ 81% of US
price level, 2025
GDP per capita
$60,750
2025
Happiness
6.9 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
1.1
per 100k, 2021
Road deaths
5.8
per 100k/yr, 2019
Income group
High
World Bank
English
Very high
EF EPI 608
Religion
Roman Catholic 57%nonbeliever/agnostic 20%atheist 9%Muslim 7%

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 Aalst (50.936°, 4.0355°, 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. 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).