Weather in Barcelona in September

Prime time. If you get to pick your dates, September is the one. Highs average 27.9 °C, lows 18.8 °C, and rain falls on 9 days — nothing in the month is working against you.

September ranks 7 of 12 in Barcelona: past the worst of the year but short of April, which is the month to book if the dates are open.

Rain on 9 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: 6 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest September day reached 36.9 °C and the coldest night fell to 9.5 °C, and the wettest single day dropped 50 mm — roughly 85% of the month's rain in one day.

September is moderately variable: 18 mm in the driest year against 119 mm in the wettest, around an average of 59 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 7.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 70%.

How September sits in the year

The month is on the way down: 3.9 °C cooler than August, with October dropping another 4 °C. The first week and the last are not the same trip.

Daylight in September

12.5 hours of daylight, losing 1.4 hours across the month. That is between Barcelona's extremes of 15.1 and 9.2 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 24.2 °C in September — warm enough to stay in as long as you like. This is the warmest the water gets all year.

How busy it gets

Shoulder. The value months — prices ease off and you get the place closer to itself. September is the value pick for Barcelona: it scores within 7 points of April without carrying April's prices.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Barcelona versus nearby

If Barcelona is one option among several, the nearby comparison is worth making. Palma is close enough to be a coin toss — 2.4 °C cooler, 1 day more rain. Toulouse is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: September works, with April the better month by 7 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Barcelona

See all twelve months in Barcelona, or where else to go in September.