Your September weather guide
WarmWeather in Barcelona in September
September is a good choice for Barcelona if you want warm days and a swimmable sea, but can accept some wet weather. Average daytime highs of 24°C suit exploring without planning everything around intense heat, and the sea is also around 24°C. The catch is rain on about 11 days, so this is not a month to count on uninterrupted sunshine. Go for a mix of city time and swimming, with flexible plans.
Long-term climate averages for Barcelona, not a forecast · 1991-2020
Barcelona, month by month
Your snapshot
At a glance
The useful details for Barcelona.
- Average daytime high
- 24.0°C
- 9 in 10 days stay below 27°C
- Average night-time low
- 17.8°C
- coldest 10% of nights: 15°C or lower
- Compared with London
- +5.4°C
- London averages 18.6°C in September
- Sea temperature
- 24.0°C
- year to year: 23°C to 25°C
- Sunshine per day (est.)
- 6.1h
- 50% of 12.3 h of daylight
- Rainy days (1 mm+)
- 11
- 79 mm over the month
- Humidity
- 78%
- Days over 25°C
- 36%
- 0% over 30°C
- Record high 1991-2020
- 30.3°C
- 2016-09-04
- Record low 1991-2020
- 8.7°C
- 1995-09-26
- Flight from London
- ≈ 2 h 6 min
- 1100 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 Barcelona and ranks 110th of 134 destinations we compare for September - see where else is hot in September. Within Spain it is 83rd of 87 (Spain in September). Against London's average high of 18.6°C in September, Barcelona is 5.4°C warmer by day and 6.6°C warmer at night.
Daytime and night-time in September
The typical September day in Barcelona peaks at 24.0°C, but that is an average: the warmest 10% of days reach 27.1°C or more. Roughly 1 in 3 days top 25°C and 1 in 1000 pass 30°C. Nights average 17.8°C; one night in ten drops to 15.0°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 30.3°C (2016-09-04) and the coldest night 8.7°C (1995-09-26).
Rain in September
Wet (more than 8 rainy days): about 11 days with 1 mm or more, 79 mm in total. Year to year it varies a lot - the wettest September was 1995 with 170 mm, the driest 1997 with 19 mm. Humidity averages 78%.
Sea temperature in September
The sea averages 24.0°C - warm enough to swim (22°c+). Depending on the year it ranges from 23.0°C to 24.7°C. For the warmest sea here, come in August (25.5°C).
Sunshine and daylight
Around 6.1 hours of sunshine a day (estimated from cloud cover), 12.3 hours of daylight: the sun rises about 07:32 and sets about 20:01 local time in mid-September. Average cloud cover is 50%.
Is September a good time to visit Barcelona?
It is a reasonable choice: warm days but expect showers. The best months for Barcelona on our scoring are July, June, August; months averaging 25°C or more: Jul, Aug.
Warm enough for summer clothes, with cooler evenings
September suits travellers who want warmth rather than very hot weather. Days reach 25°C around 36% of the time, so there is still scope for afternoons that feel properly summery. The warmer days reach 27°C or more, making shade and a break at midday sensible if you are walking a lot. Humidity averages 78%, which can make the warmth feel less comfortable than the temperature alone suggests. Light clothing is a useful starting point, but bring a layer for evenings: the average night low is around 18°C, and the cooler nights fall to 15°C or below. Do not pack solely for heat.
Plan for sunshine, but leave room for rain
Rain is the main compromise in September, so keep outdoor plans movable rather than treating every day as a beach day. About 6.1 hours of sunshine within 12.3 hours of daylight leaves useful time outdoors, but does not promise clear skies throughout the day. A light waterproof and shoes you can comfortably wear in wet conditions are sensible additions to your bag. Check the forecast before committing to a long spell outside, and keep an indoor alternative available. If your main aim is swimming with some time exploring, September makes sense; if reliable dry weather is essential to your holiday, the rainfall is a reason to be cautious.
A little perspective
Barcelona through the year
September is highlighted. See how it compares with the rest of the year.
| Month | Day | Night | Sea | Sun/day | Rain mm | Rainy days | Days 25°C+ |
|---|---|---|---|---|---|---|---|
| January | 12.5°C | 5.1°C | 13.5°C | 4.8 | 41 | 6 | 0% |
| February | 13.2°C | 5.4°C | 12.9°C | 5.4 | 35 | 6 | 0% |
| March | 15.5°C | 7.4°C | 13.2°C | 6.0 | 41 | 7 | 0% |
| April | 17.3°C | 9.6°C | 14.3°C | 6.5 | 54 | 9 | 0% |
| May | 20.6°C | 13.2°C | 17.0°C | 6.9 | 46 | 7 | 7% |
| Junebest | 24.6°C | 17.2°C | 20.7°C | 8.9 | 36 | 6 | 44% |
| Julybest | 27.2°C | 20.2°C | 24.0°C | 10.0 | 23 | 5 | 83% |
| Augustbest | 27.4°C | 20.8°C | 25.5°C | 8.3 | 40 | 7 | 85% |
| SeptemberSelected | 24.0°C | 17.8°C | 24.0°C | 6.1 | 79 | 11 | 36% |
| October | 20.5°C | 14.3°C | 21.0°C | 4.8 | 92 | 10 | 4% |
| November | 16.0°C | 9.4°C | 17.4°C | 4.6 | 61 | 8 | 0% |
| December | 13.1°C | 6.2°C | 14.9°C | 4.5 | 42 | 6 | 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
- Sea
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.
Portugal · 24°C by day · sea 24°C
Madeira
Italy · 24°C by day · sea 24°C
Amalfi Coast
Italy · 24°C by day · sea 24°C
Sorrento
Montenegro · 25°C by day · sea 24°C
Budva
France · 24°C by day · sea 23°C
Nice
A little more detail
Barcelona in September FAQs
Plain answers, grounded in the averages.
Is Barcelona hot in September?
Barcelona is warm in September: the average daytime high is 24.0°C and nights average 17.8°C. Roughly 1 in 3 September days reach 25°C.
Can you swim in the sea in Barcelona in September?
The sea around Barcelona averages 24.0°C in September, which is warm enough for most people to swim comfortably. Between 1991 and 2020 it ranged from 23°C to 25°C depending on the year.
How much does it rain in Barcelona in September?
Barcelona sees about 11 rainy days (1 mm or more) and 79 mm of rain in a typical September. The wettest September between 1991 and 2020 was 1995 (170 mm) and the driest was 1997 (19 mm).
How sunny is Barcelona in September?
Barcelona gets around 6.1 hours of sunshine a day in September out of 12.3 hours of daylight (estimated from average cloud cover).
How does Barcelona compare with the UK in September?
Barcelona is on average 5.4°C warmer than London by day in September (24.0°C against 18.6°C).
What is the hottest September on record in Barcelona?
Between 1991 and 2020 the hottest September day in Barcelona reached 30.3°C on 2016-09-04, and the coldest night dropped to 8.7°C on 1995-09-26.
Is the sea warm enough to swim in September?
Yes. The sea averages 24°C, with a year-to-year range of 23°C to 25°C, putting it comfortably in the swimming category. Sea temperature is a reason to go, though rain may still affect when you choose to swim.
How much warmer is Barcelona than London in September?
Barcelona's average daytime high is 24°C, compared with London's 18.6°C, a difference of 5.4°C. That is a noticeable step up in warmth for a UK traveller, although cooler evenings mean a light layer still deserves space in your bag.
About these averages
ERA5-Land climate reanalysis via Open-Meteo (11 km grid) and NOAA Coral Reef Watch 5 km sea temperatures, 1991-2020
Averages computed from daily values at Barcelona. Sea temperature from the nearest 5 km sea cell, 2 km from that point. 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