August is the hottest month of the year in Barcelona: 30°C during the day, 22.8°C at night, and a sea temperature of 26.5°C. It rains on average only three days, but the heat has become more frequent, with fifteen days at 30°C or more compared to nine in the 1991-2020 average.
Temperatures, rain and sunshine: AEMET station 0076 (Barcelona Aeropuerto), 2016-2025 averages against the 1991-2020 normal. Sea: NOAA OISST, same period. Daylight runs from 14 hr 25 min to 13 hr 12 min across the month.
Early, Mid, or Late August?
The weather changes throughout the month. If you're deciding between several dates, here's what sets each period apart. Averages per decade over ten years, AEMET station 0076.
August 1st → 10th
30.5°C / 23.3°C, 5 mm of rain.
This is the true peak of the year's heat: no other ten-day period has higher temperatures. It's also the driest of the summer, with only five millimeters of rain, while the sea continues to warm up.
August 11 → 20
30°C / 22.9°C, 17 mm of rain.
The heat remains almost the same as at the beginning of the month. What changes most is the risk of thunderstorms: precipitation increases significantly, often in the form of late afternoon showers that are generally quite brief.
August 21 → 31
29.4°C / 22.2°C, 23 mm of rain.
Temperatures are dropping slightly, but rain is becoming more frequent. However, the sea reaches its annual peak, maintaining excellent swimming conditions even though the days have already lost nearly an hour since the 1st.
What to Pack in Your Suitcase
Essentials
- Very light clothing, in cotton or linen: fifteen days of the month exceed 30°C
- A swimsuit and a towel: the sea reaches 26.5°C, its highest temperature of the year
- Sunscreen with SPF 50: August has 274 hours of sunshine, nearly nine hours per day
- Closed and comfortable shoes for sightseeing, especially in the Gothic Quarter and on the slopes of Montjuïc
- A water bottle to stay hydrated throughout the day
Still worth considering
- A light sweater, especially for the air conditioning in museums and the metro, as evenings remain around 22.2°C at the end of the month
- Something to cover your shoulders: the Sagrada Família and the cathedral require it for entry
- A thin windbreaker for the late-month storms: the last ten days receive 23 mm compared to 5 mm for the first
- A compact umbrella is usually sufficient: showers are often brief and it only rains an average of three days
Swimming in Barcelona in August
August offers the warmest sea of the year, with an average of 26.5°C. It will remain pleasantly warm for several more weeks: even in October, it reaches 22.2°C, which is comparable to the temperature in June.
At 26.5°C, the water is enjoyable at any time, including in the evening. Swimming at the end of the day is particularly delightful, with less sun and a sea that retains all its warmth.
When it's 30°C
Where to Cool Off When It's Very Hot
Fifteen days of the month exceed 30°C. Between noon and four in the afternoon, it's best to avoid long visits in direct sunlight and opt for air-conditioned places, the beach, or routes that avoid uphill climbs.
Cool Off
L’Aquàrium de Barcelona
Keeping Cool
CosmoCaixa
Without the climb
Telefèric de Montjuïc (Montjuïc Cable Car)
On the Agenda
What to Do in Barcelona in August?
August is bustling despite the heat: Gràcia Festival, Sala Montjuïc, Brunch Electronik, and numerous outdoor events keep the month lively. It's also the time when many Barcelonans leave the city for vacation.
August or September?
September sees a drop of -3.2°C in maximum temperatures while maintaining a sea temperature of 25.1°C, only slightly cooler than in August. However, it is wetter, with 68 mm over six days compared to 45 mm over three. If you don't handle heat well, September offers almost as pleasant swimming with fewer days above 30°C.
| July | August | September | |
|---|---|---|---|
| Maximum | 29.3°C | 30°C | 26.8°C |
| Minimum | 22.5°C | 22.8°C | 19.2°C |
| Sea | 25.2°C | 26.5°C | 25.1°C |
| Rain | 27 mm | 45 mm | 68 mm |
| Sunshine | 302 h | 274 h | 217 h |
| Rainy days | 2 | 3 | 6 |
August in the Year
August is the peak of the year with an average high of 30°C. July is very close, while temperatures start to drop more noticeably in September.
Frequently Asked Questions About August in Barcelona
August is very hot, with an average high of 30°C and fifteen days at 30°C or more, compared to nine in the 1991-2020 average. The hottest days reach around 33.8°C. To visit comfortably, it's best to go out in the morning and late afternoon, and reserve the middle of the day for the beach or air-conditioned places.
Yes, it's even the month when the sea is the warmest: an average of 26.5°C, with a very pleasant temperature from morning to evening. Late swims are particularly enjoyable.
It rarely rains, but showers can be intense. August receives 45 mm spread over just three days, often in the form of late afternoon thunderstorms, more frequent in the second half of the month. September is wetter, with 68 mm over six days.
August boasts 274 hours of sunshine, which is nearly nine hours per day. However, the length of the day decreases significantly, from 14 hours and 25 minutes on August 1st to 13 hours and 12 minutes on the 31st.
September is often more comfortable if you have flexible dates: it drops -3.2°C on the maximum temperatures while maintaining a sea temperature of 25.1°C. However, it is rainier, with 68 mm over six days compared to 45 mm over three. August remains the best choice for a very warm sea and a full summer vacation.