Tønder weather in September

In September, Tønder sees average daytime highs of 17°C and overnight lows near 12°C, with 84 mm of rain across 13.1 wet days and about 12.5 hours of daylight. It is the 4th-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 18°C in the first days to 15°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 36 min at the start of September to 11 h 24 min by month's end. Set against the rest of the year, September is Tønder's 6th-clearest and 7th-windiest month. For the whole year in context, see Tønder's year-round climate.

Daytime high
17°
4th warmest
Overnight low
12°
10th coldest
Rainfall
84 mm
13.1 wet days
Daylight
12 h 24 min
6:06 AM – 6:32 PM
Cloud cover
68%
6th clearest
Wind
19 km/h
7th windiest
Solar energy
2.8 kWh/m²
Travel score
4.7
out of 10

Tønder is town in Denmark.

Density
2,415/km²
people per km²
Founded
1017

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 18°C in the first days to 15°C by the end.

A typical September day in Tønder reaches about 17°C in the afternoon and slips back to 12°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 14°C and 20°C. Set against its neighbours, September runs about 3°C cooler than August and about 4°C warmer than October.

10°15°20°25°151015202530
Avg high (°C)Avg low (°C)
11813
21813
31813
41813
51813
61813
71813
81813
91713
101713
111713
121712
131712
141712
151712
161712
171612
181612
191612
201612
211612
221611
231611
241611
251511
261511
271511
281511
291511
301511

How September really feels in Tønder

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.

Tønder weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 7313.92.77.60.0
Feb / 5611.12.79.30.0
Mar / 5511.2211.40.5
Apr10° / 429.60.313.82.4
May14° / 5110.4015.84.2
Jun17° / 12°7111.20175.2
Jul19° / 14°7812.6016.55.8
Aug20° / 14°9114014.75.7
Sep17° / 12°8413.1012.54.7
Oct12° / 8914.2010.22.9
Nov / 7713.90.48.11.2
Dec / 77141.770.1

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 19% of September, with mostly cloudy or overcast conditions the remaining 65%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14060
24060
34060
43961
53862
63961
73862
83763
93763
103664
113664
123664
133664
143664
153664
163565
173565
183565
193466
203466
213268
223268
233169
243169
253169
263169
273169
283268
293268
303169

Chance of precipitation in September

Any precipitation

Tønder gets around 84 mm of rain over 13.1 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 45% and peaks near 47% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
147
247
347
447
547
647
746
846
946
1046
1146
1245
1345
1445
1544
1644
1744
1843
1943
2043
2142
2242
2342
2443
2543
2643
2744
2844
2945
3045

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 73% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1583561
2603550
3603550
4623440
5623440
6633340
7643330
8653230
9663130
10673030
11682930
12692830
13702730
14712630
15732520
16752320
17762220
18762220
19782110
20792010
21792010
22792010
23801910
24811900
25821800
26821800
27831700
28841600
29841600
30851500

Wind in September

Winds average 19 km/h in September.

Across September, daily wind ranges from about 18 km/h on the calmest days to 19 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202530
Wind speed (km/h)Feels
118light breeze
218light breeze
318light breeze
418light breeze
518light breeze
619light breeze
719light breeze
819light breeze
919light breeze
1019light breeze
1119light breeze
1219light breeze
1319light breeze
1419light breeze
1519light breeze
1619light breeze
1719light breeze
1819light breeze
1919light breeze
2019light breeze
2119light breeze
2219light breeze
2319light breeze
2419light breeze
2519light breeze
2619light breeze
2719light breeze
2819light breeze
2919light breeze
3019light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 36 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 132 minutes over September. Sunrise moves from 5:37 AM to 6:33 AM, and sunset from 7:12 PM to 5:55 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.65:377:12
213.55:397:09
313.45:417:06
413.45:437:04
513.35:457:01
613.25:466:59
713.15:486:56
813.15:506:53
913.05:526:51
1012.95:546:48
1112.85:566:45
1212.75:586:43
1312.76:006:40
1412.66:026:37
1512.56:046:35
1612.46:066:32
1712.46:086:29
1812.36:096:27
1912.26:116:24
2012.16:136:21
2112.16:156:19
2212.06:176:16
2311.96:196:13
2411.86:216:11
2511.86:236:08
2611.76:256:05
2711.66:276:03
2811.56:296:00
2911.46:315:58
3011.46:335:55

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 2.8 kWh/m².

For context, solar energy here swings from a low near 0.4 kWh/m² to a high of 5.64 kWh/m² in June across the year — September's 2.8 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.5Moderate
23.5Moderate
33.4Moderate
43.4Moderate
53.3Moderate
63.3Moderate
73.2Moderate
83.2Moderate
93.1Moderate
103.1Moderate
113.0Moderate
123.0Moderate
132.9Moderate
142.9Moderate
152.8Moderate
162.8Moderate
172.7Moderate
182.7Moderate
192.6Moderate
202.6Moderate
212.5Moderate
222.5Moderate
232.4Moderate
242.4Moderate
252.4Moderate
262.3Moderate
272.3Moderate
282.2Moderate
292.2Moderate
302.1Moderate
Planning a trip in September

Is September a good time to visit Tønder?

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

4.7
Sightseeing
4th-best month of the year
1.0
Beach & pool
4th-best month of the year

September is a reasonable time to visit Tønder for sightseeing.

What to pack for Tønder in September

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

In September, Tønder sees daytime highs around 17°C and nights near 12°C. Worth packing: a warm layer and rain gear. About 13 days see rain.

a warm layerrain gear

Sea temperature near Tønder in September

The nearest coast averages about 16°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 17 km away) is warmest in August at about 19°C and coldest in February near 3°C.

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

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan4Bracing
Feb3Bracing
Mar4Bracing
Apr7Bracing
May11Bracing
Jun15Bracing
Jul18Cool
Aug19Cool
Sep16Cool
Oct12Bracing
Nov9Bracing
Dec5Bracing

UV index in Tønder 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 Tønder peaks around July 21 at about 5 (high) — a little sun protection helps at midday. It bottoms out near January 1 at about 0 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJul 21UV 5Jan 1UV 0
UV index (midday)Level
Jan0Low
Feb1Low
Mar2Moderate
Apr3Moderate
May5High
Jun5High
Jul6High
Aug5High
Sep4Moderate
Oct2Low
Nov1Low
Dec0Low
Location & terrain

Where is Tønder?

Tønder sits at 54.9°N, 8.9°E, 3 m above sea level, in Denmark. The nearest listed city is Aabenraa, 37 km away.

AabenraaFlensburgHusumHaderslevSønderborgSchleswigEsbjergKolding

Topography around Tønder

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

Within 3 km, the terrain around Tønder has only modest variations in elevation — a maximum elevation change of 16 m around an average of 2 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 50 m; within 80 km, only modest variations in elevation — a maximum elevation change of 123 m.

The land around Tønder is covered by cropland (43%) and grassland (37%) within 3 km, cropland (50%) and grassland (34%) within 16 km, and water (40%), cropland (29%) and grassland (20%) within 80 km.

3 km
16 m
16 km
50 m
80 km
123 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Aabenraa 37 km · Flensburg 40 km · Husum 51 km · Haderslev 53 km · Sønderborg 59 km · Schleswig 64 km · Esbjerg 65 km · Kolding 73 km

Denmark travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / E / F / K
230 V · 50 Hz
Prices
≈ 92% of US
price level, 2025
GDP per capita
$76,970
2025
Happiness
7.5 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
0.8
per 100k, 2023
Road deaths
3.7
per 100k/yr, 2019
Income group
High
World Bank
English
Very high
EF EPI 611
Religion
Evangelical Lutheran 71%other/none/unspecified 24%Muslim 4%

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 Tønder (54.9331°, 8.8667°, elevation 3 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).