Frederikssund weather in September

In September, Frederikssund sees average daytime highs of 17°C and overnight lows near 10°C, with 56 mm of rain across 9.9 wet days and about 12.5 hours of daylight. It is the 4th-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 19°C in the first days to 15°C by the end. The sky is clear or mostly clear about 20% 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 18 min by month's end. Set against the rest of the year, September is Frederikssund's 6th-clearest and 7th-windiest month. For the whole year in context, see Frederikssund's year-round climate.

Daytime high
17°
4th warmest
Overnight low
10°
9th coldest
Rainfall
56 mm
9.9 wet days
Daylight
12 h 30 min
5:52 AM – 6:20 PM
Cloud cover
67%
6th clearest
Wind
16 km/h
7th windiest
Solar energy
2.88 kWh/m²
Travel score
5.3
out of 10

Frederikssund is town in Denmark.

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 19°C in the first days to 15°C by the end.

A typical September day in Frederikssund reaches about 17°C in the afternoon and slips back to 10°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 14°C and 21°C. Set against its neighbours, September runs about 4°C cooler than August and about 5°C warmer than October.

10°15°20°25°151015202530
Avg high (°C)Avg low (°C)
11912
21912
31912
41911
51911
61811
71811
81811
91811
101811
111811
121811
131710
141710
151710
161710
171710
181710
191710
201610
211610
221610
23169
24169
25169
26169
27159
28159
29159
30159

How September really feels in Frederikssund

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.

Frederikssund weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -1°4710.947.40.0
Feb / -1°3893.99.20.0
Mar / 419.62.411.40.6
Apr11° / 419.60.413.82.8
May16° / 5510.70164.8
Jun19° / 11°6911.4017.25.8
Jul21° / 13°7111.8016.76.2
Aug21° / 13°7312.1014.86.1
Sep17° / 10°569.9012.55.3
Oct12° / 5711010.13.1
Nov / 4610.50.981.0
Dec / 4910.92.86.80.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 20% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 63%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14060
24060
34060
44060
53961
63961
74060
83961
93961
103961
113961
123862
133862
143763
153763
163664
173664
183664
193664
203664
213664
223565
233466
243466
253565
263565
273565
283565
293565
303565

Chance of precipitation in September

Any precipitation

Frederikssund gets around 56 mm of rain over 9.9 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 34% and peaks near 38% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
138
238
338
437
537
637
737
836
936
1035
1135
1234
1334
1433
1533
1632
1732
1831
1931
2031
2130
2230
2331
2431
2531
2632
2732
2833
2933
3033

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 82% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
167285
268284
370273
470273
572262
673252
773252
875241
976231
1077221
1178211
1279201
1380191
1482180
1583170
1684160
1785150
1886140
1987130
2088120
2189110
2289110
2390100
2490100
259190
269190
279190
289280
299280
309370

Wind in September

Winds average 16 km/h in September.

Across September, daily wind ranges from about 15 km/h on the calmest days to 17 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
115light breeze
215light breeze
316light breeze
416light breeze
516light breeze
616light breeze
716light breeze
816light breeze
916light breeze
1016light breeze
1116light breeze
1216light breeze
1317light breeze
1417light breeze
1517light breeze
1617light breeze
1717light breeze
1816light breeze
1916light breeze
2016light breeze
2116light breeze
2216light breeze
2316light breeze
2416light breeze
2516light breeze
2616light breeze
2717light breeze
2817light breeze
2917light breeze
3017light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 36 min at the start of September to 11 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 138 minutes over September. Sunrise moves from 5:22 AM to 6:21 AM, and sunset from 7:00 PM to 5:41 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.65:227:00
213.65:246:58
313.55:266:55
413.45:286:52
513.35:306:50
613.25:326:47
713.25:346:44
813.15:366:42
913.05:386:39
1012.95:406:36
1112.95:426:33
1212.85:446:31
1312.75:466:28
1412.65:486:25
1512.55:506:22
1612.55:526:20
1712.45:546:17
1812.35:566:14
1912.25:586:11
2012.16:006:09
2112.16:026:06
2212.06:046:03
2311.96:066:00
2411.86:085:58
2511.76:105:55
2611.76:135:52
2711.66:155:50
2811.56:175:47
2911.46:195:44
3011.36:215:41

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 2.88 kWh/m².

For context, solar energy here swings from a low near 0.38 kWh/m² to a high of 5.75 kWh/m² in June across the year — September's 2.88 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.6Moderate
23.6Moderate
33.5Moderate
43.5Moderate
53.4Moderate
63.4Moderate
73.3Moderate
83.3Moderate
93.2Moderate
103.1Moderate
113.1Moderate
123.0Moderate
133.0Moderate
142.9Moderate
152.9Moderate
162.8Moderate
172.8Moderate
182.7Moderate
192.7Moderate
202.6Moderate
212.6Moderate
222.5Moderate
232.5Moderate
242.5Moderate
252.4Moderate
262.4Moderate
272.3Moderate
282.3Moderate
292.2Moderate
302.2Moderate
Planning a trip in September

Is September a good time to visit Frederikssund?

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

5.3
Sightseeing
4th-best month of the year
1.3
Beach & pool
4th-best month of the year

September is a reasonable time to visit Frederikssund for sightseeing.

What to pack for Frederikssund in September

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

In September, Frederikssund sees daytime highs around 17°C and nights near 10°C. Worth packing: rain gear. About 10 days see rain.

rain gear

Sea temperature near Frederikssund 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 13 km away) is warmest in August at about 19°C and coldest in February near 2°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
Jan3Bracing
Feb2Bracing
Mar3Bracing
Apr6Bracing
May11Bracing
Jun15Cool
Jul18Cool
Aug19Cool
Sep16Cool
Oct12Bracing
Nov8Bracing
Dec5Bracing

UV index in Frederikssund 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 Frederikssund peaks around July 11 at about 5 (high) — a little sun protection helps at midday. It bottoms out near December 20 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 11UV 5Dec 20UV 0
UV index (midday)Level
Jan0Low
Feb1Low
Mar2Moderate
Apr3Moderate
May5Moderate
Jun5High
Jul5High
Aug5Moderate
Sep4Moderate
Oct2Low
Nov1Low
Dec0Low
Location & terrain

Where is Frederikssund?

Frederikssund sits at 55.8°N, 12.1°E, 17 m above sea level, in Denmark. The nearest listed city is Stenløse, 11 km away.

Topography around Frederikssund

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

Within 3 km, the terrain around Frederikssund has only modest variations in elevation — a maximum elevation change of 63 m around an average of 10 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 85 m; within 80 km, significant variations in elevation — a maximum elevation change of 273 m.

The land around Frederikssund is covered by water (25%) and grassland (24%) within 3 km, cropland (28%), water (28%) and grassland (23%) within 16 km, and water (52%) and cropland (23%) within 80 km.

3 km
63 m
16 km
85 m
80 km
273 m
treesgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: Stenløse 11 km · Hillerød 17 km · Lillerød 18 km · Allerød 18 km · Farum 19 km · Ballerup 22 km · Roskilde 22 km · Birkerød 22 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 Frederikssund (55.8396°, 12.069°, elevation 17 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).