Kalmthout weather in September

In September, Kalmthout sees average daytime highs of 19°C and overnight lows near 12°C, with 59 mm of rain across 11 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 20°C in the first days to 17°C by the end. The sky is clear or mostly clear about 17% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 24 min at the start of September to 11 h 24 min by month's end. Set against the rest of the year, September is Kalmthout's 3rd-clearest and 9th-windiest month. For the whole year in context, see Kalmthout's year-round climate.

Daytime high
19°
4th warmest
Overnight low
12°
9th coldest
Rainfall
59 mm
11 wet days
Daylight
12 h 24 min
6:25 AM – 6:48 PM
Cloud cover
67%
3rd clearest
Wind
13 km/h
9th windiest
Solar energy
3.03 kWh/m²
Travel score
5.7
out of 10

Kalmthout is town in Kalmthout municipality, Belgium.

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 20°C in the first days to 17°C by the end.

A typical September day in Kalmthout reaches about 19°C in the afternoon and slips back to 12°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 23°C. Set against its neighbours, September runs about 3°C cooler than August and about 4°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12113
22013
32013
42013
52012
62012
72012
82012
92012
102012
111912
121912
131912
141912
151912
161911
171911
181911
191911
201811
211811
221811
231811
241811
251811
261811
271711
281710
291710
301710

How September really feels in Kalmthout

Once humidity and wind are folded in, September 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

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

Kalmthout weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 6311.918.20.4
Feb / 55111.59.60.7
Mar10° / 5411.50.711.52.2
Apr14° / 4710.80.113.54.0
May18° / 6212.1015.35.4
Jun20° / 12°6611.1016.36.0
Jul22° / 14°7713.4015.96.2
Aug22° / 14°7612.3014.46.2
Sep19° / 12°5911012.45.7
Oct15° / 6211.3010.44.1
Nov10° / 6412.20.48.61.9
Dec / 7413.41.17.70.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 65%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13466
23466
33565
43565
53565
63664
73664
83664
93664
103664
113763
123664
133763
143664
153664
163763
173763
183664
193763
203664
213664
223565
233466
243466
253367
263268
273169
283070
292971
302872

Chance of precipitation in September

Any precipitation

Kalmthout gets around 59 mm of rain over 11 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 37% and peaks near 43% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
137
236
336
436
535
635
735
836
936
1036
1136
1236
1336
1436
1536
1636
1736
1837
1937
2037
2137
2238
2338
2439
2540
2640
2741
2842
2942
3043

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the dry band about 68% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
15434111
25533111
35632111
45831101
56030100
66129100
76129100
86228100
96327100
106327100
11652690
12662590
13682480
14682480
15702370
16702370
17712360
18722350
19732340
20732340
21742330
22732430
23742420
24742420
25752410
26752410
27752410
28752410
29762310
30762310

Wind in September

Winds average 13 km/h in September.

Across September, 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.

05101520151015202530
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
2714light breeze
2814light breeze
2914light breeze
3014light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 24 min at the start of September to 11 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 120 minutes over September. Sunrise moves from 6:00 AM to 6:48 AM, and sunset from 7:23 PM to 6:15 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.46:007:23
213.36:027:21
313.36:047:19
413.26:057:16
513.16:077:14
613.16:087:12
713.06:107:09
812.96:127:07
912.96:137:05
1012.86:157:02
1112.76:177:00
1212.76:186:58
1312.66:206:55
1412.56:226:53
1512.56:236:50
1612.46:256:48
1712.36:266:46
1812.36:286:43
1912.26:306:41
2012.16:316:38
2112.16:336:36
2212.06:356:34
2311.96:366:31
2411.86:386:29
2511.86:406:27
2611.76:416:24
2711.66:436:22
2811.66:456:19
2911.56:466:17
3011.46:486:15

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.03 kWh/m².

For context, solar energy here swings from a low near 0.6 kWh/m² to a high of 5.27 kWh/m² in June across the year — September's 3.03 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.6Moderate
23.6Moderate
33.5Moderate
43.5Moderate
53.5Moderate
63.4Moderate
73.4Moderate
83.3Moderate
93.3Moderate
103.3Moderate
113.2Moderate
123.2Moderate
133.1Moderate
143.1Moderate
153.1Moderate
163.0Moderate
173.0Moderate
182.9Moderate
192.9Moderate
202.9Moderate
212.8Moderate
222.8Moderate
232.7Moderate
242.7Moderate
252.6Moderate
262.6Moderate
272.5Moderate
282.5Moderate
292.4Moderate
302.4Moderate
Planning a trip in September

Is September a good time to visit Kalmthout?

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

5.7
Sightseeing
4th-best month of the year
2.4
Beach & pool
4th-best month of the year

September is a reasonable time to visit Kalmthout for sightseeing.

What to pack for Kalmthout in September

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

In September, Kalmthout sees daytime highs around 19°C and nights near 12°C. Worth packing: rain gear. About 11 days see rain.

rain gear

Sea temperature near Kalmthout in September

The nearest coast averages about 18°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 65 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
Jun15Cool
Jul18Cool
Aug19Cool
Sep18Cool
Oct15Bracing
Nov11Bracing
Dec8Bracing

UV index in Kalmthout in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September 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 Kalmthout 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 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJun 23UV 6Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May6High
Jun6High
Jul6High
Aug6High
Sep4Moderate
Oct2Moderate
Nov1Low
Dec1Low
Location & terrain

Where is Kalmthout?

Kalmthout sits at 51.4°N, 4.5°E, 21 m above sea level, in Belgium. The nearest listed city is Kapellen, 8.0 km away.

MerksemRoosendaalSchilde

Topography around Kalmthout

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

Within 3 km, the terrain around Kalmthout has only modest variations in elevation — a maximum elevation change of 36 m around an average of 24 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 57 m; within 80 km, only modest variations in elevation — a maximum elevation change of 188 m.

The land around Kalmthout is covered by trees (44%) and grassland (34%) within 3 km, trees (36%), grassland (27%) and cropland (20%) within 16 km, and grassland (28%), cropland (24%) and trees (21%) within 80 km.

3 km
36 m
16 km
57 m
80 km
188 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Kapellen 8.0 km · Stabroek 9.0 km · Brasschaat 10 km · Ekeren 12 km · Schoten 15 km · Merksem 15 km · Roosendaal 16 km · Schilde 18 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 Kalmthout (51.3844°, 4.4756°, elevation 21 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).