Your September weather guide
MildWeather in Copenhagen in September
September is a good fit for Copenhagen if you prefer mild city-break weather to heat, but you need to be comfortable with rain. Average daytime highs of 16.7°C suit being out and about in layers, while nights around 11.7°C call for a jacket. With about 10 rainy days, outdoor plans need some flexibility. Go for comfortable walking weather rather than reliable sunshine, and leave room to change plans when it turns wet.
Long-term climate averages for Copenhagen, not a forecast · 1991-2020
Copenhagen, month by month
Your snapshot
At a glance
The useful details for Copenhagen.
- Average daytime high
- 16.7°C
- 9 in 10 days stay below 20°C
- Average night-time low
- 11.7°C
- coldest 10% of nights: 8°C or lower
- Compared with London
- -1.9°C
- London averages 18.6°C in September
- Sunshine per day (est.)
- 4.5h
- 36% of 12.4 h of daylight
- Rainy days (1 mm+)
- 11
- 58 mm over the month
- Humidity
- 79%
- Days over 25°C
- 0%
- none over 30°C
- Record high 1991-2020
- 24.1°C
- 2016-09-13
- Record low 1991-2020
- 4.5°C
- 2002-09-24
- Flight from London
- ≈ 2 h
- 982 km, short-haul (estimate for a direct flight)
Records are observed extremes within 1991-2020, not typical holiday conditions. Warm-day percentages are shares of days, not day counts.
How September compares
September is the 4th warmest month of the year in Copenhagen. Against London's average high of 18.6°C in September, Copenhagen is 1.9°C cooler by day and 0.5°C warmer at night.
Daytime and night-time in September
The typical September day in Copenhagen peaks at 16.7°C, but that is an average: the warmest 10% of days reach 20.1°C or more. Days over 25°C are rare. Nights average 11.7°C; one night in ten drops to 8.4°C or lower, so pack a layer for evenings - it is genuinely cool after dark. Between 1991 and 2020 the hottest September day here reached 24.1°C (2016-09-13) and the coldest night 4.5°C (2002-09-24).
Rain in September
Wet (more than 8 rainy days): about 11 days with 1 mm or more, 58 mm in total. Year to year it varies a lot - the wettest September was 1994 with 119 mm, the driest 2002 with 19 mm. Humidity averages 79%.
Sunshine and daylight
Around 4.5 hours of sunshine a day (estimated from cloud cover), 12.4 hours of daylight: the sun rises about 06:42 and sets about 19:28 local time in mid-September. Average cloud cover is 64%.
Is September a good time to visit Copenhagen?
September is not the strongest month here: mild days and frequent rain. The best months for Copenhagen on our scoring are July, August, June.
Mild afternoons, cooler evenings
Copenhagen feels a little cooler than London in September, where the average daytime high is 18.6°C. That makes it a reasonable choice if you find summer heat tiring, though not if warmth is the main reason for your trip. The warmer days can reach 20.1°C or more, so a lighter layer may be enough during a mild afternoon. At the colder end, nights can fall to 8.4°C or below, making a warm jumper useful if you plan to stay out late. Dress so you can add or remove layers rather than relying on the same outfit from morning to evening.
Plan for rain, not constant gloom
Rain is the main catch: September is a wet month, so a waterproof outer layer is more useful than packing only for dry afternoons. The rainy-day average does not mean every wet day is a write-off, but it does make a rigid outdoor schedule a poor fit. There are about 4.5 hours of sunshine a day within 12.4 hours of daylight, leaving scope for time outside without promising clear skies throughout. Keep your longer walks flexible and have an indoor alternative ready. Shoes that cope with wet conditions will also make the trip more comfortable than footwear chosen only for mild temperatures.
A little perspective
Copenhagen through the year
September is highlighted. See how it compares with the rest of the year.
| Month | Day | Night | Sun/day | Rain mm | Rainy days | Days 25°C+ |
|---|---|---|---|---|---|---|
| January | 3.0°C | -0.4°C | 1.8 | 50 | 12 | 0% |
| February | 3.3°C | -0.6°C | 2.4 | 42 | 10 | 0% |
| March | 6.0°C | 0.6°C | 3.8 | 43 | 10 | 0% |
| April | 10.7°C | 3.8°C | 5.7 | 41 | 10 | 0% |
| May | 15.3°C | 8.0°C | 6.9 | 52 | 10 | 0% |
| Junebest | 18.4°C | 11.8°C | 7.1 | 73 | 12 | 3% |
| Julybest | 20.9°C | 14.3°C | 7.0 | 72 | 12 | 12% |
| Augustbest | 20.5°C | 14.6°C | 5.9 | 76 | 13 | 9% |
| SeptemberSelected | 16.7°C | 11.7°C | 4.5 | 58 | 11 | 0% |
| October | 11.8°C | 7.8°C | 3.1 | 61 | 12 | 0% |
| November | 7.2°C | 4.1°C | 1.9 | 50 | 11 | 0% |
| December | 4.2°C | 1.0°C | 1.5 | 54 | 12 | 0% |
Day = average daytime high, night = average night-time low, 1991-2020.Sun is hours per day; rainy days count 1 mm or more.
Day, night and sea
Monthly average temperatures, 1991-2020
- Day
- Night
Best months here
On warmth, low rainfall and sunshine, start with these.
Keep exploring
Similar in September
Closest matches on daytime temperature, sea temperature and sunshine, in other countries.
A little more detail
Copenhagen in September FAQs
Plain answers, grounded in the averages.
Is Copenhagen hot in September?
Copenhagen is mild in September: the average daytime high is 16.7°C and nights average 11.7°C. Days over 25°C are rare in September.
How much does it rain in Copenhagen in September?
Copenhagen sees about 11 rainy days (1 mm or more) and 58 mm of rain in a typical September. The wettest September between 1991 and 2020 was 1994 (119 mm) and the driest was 2002 (19 mm).
How sunny is Copenhagen in September?
Copenhagen gets around 4.5 hours of sunshine a day in September out of 12.4 hours of daylight (estimated from average cloud cover).
How does Copenhagen compare with the UK in September?
Copenhagen is on average 1.9°C cooler than London by day in September (16.7°C against 18.6°C).
What is the hottest September on record in Copenhagen?
Between 1991 and 2020 the hottest September day in Copenhagen reached 24.1°C on 2016-09-13, and the coldest night dropped to 4.5°C on 2002-09-24.
What should I pack for Copenhagen in September?
Pack light layers, a warm jumper and a waterproof jacket, plus shoes suitable for wet conditions. Mild afternoons may feel comfortable without heavy clothing, but cooler nights mean you should not rely on a light daytime outfit for the evening.
Would summer be a better choice for weather?
July, August and June are the stronger weather choices overall. September still suits travellers who prefer mild conditions, but it is less suited to a trip built around warmth. Choose it with layers and flexible outdoor plans in mind.
About these averages
ERA5-Land climate reanalysis via Open-Meteo (11 km grid), 1991-2020
Averages computed from daily values at Copenhagen. Sunshine hours are estimated from average cloud cover.Records are the highest and lowest daily values in that 30-year period, not all-time records. These are climate averages, not a forecast for your trip. How we measure holiday weather
- Hot · 25°C+
- Warm · 20°C to below 25°C
- Mild · 15°C to below 20°C
- Cool · below 15°C