Lisbon weather in August
Temperature, sea and sunshine in August: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in August
Excellent
Best time to visit: May – September
What is the weather like in Lisbon in August?
In August, Lisbon is warm: daytime highs average 24 °C, and nights cool down to about 18 °C. The sea averages 18.6 °C – bracing, so a wetsuit helps for longer swims. With around 10 hours of sunshine a day, there is plenty of sun. It hardly ever rains. All in all, August is an excellent month for a holiday in Lisbon.
August compared
How the weather changes from July to September. Tap a month to open it.
| JulyJul | AugustAug | SeptemberSep | |
|---|---|---|---|
| Score | 100 | 100 | 97 |
| Day | 24° | 24° | 23° |
| Night | 18° | 18° | 18° |
| Sea | 18° | 19° | 19° |
| Sun | 11 h | 10 h | 8 h |
| Rain days | 1 | 1 | 4 |
More details for August
- Daylight
- 13 h 43 min06:50 – 20:33
- UV index
- 9 · very highclear sky, noon (estimate)All months
- Muggy days
- 3 daysdew point 18 °C or more
- Wind
- 24 km/haverage daily peak
- Cloud cover
- 26 %on average
- Hot days
- 1 day30 °C or more
- Time zone
- UTC+1Europe/Lisbon
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %100 %
- Few rainy daysweight 30 %100 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in August
- Wetsuit for longer swims
- Sunscreen
- Sunglasses & sun hat
Lisbon in August: quick answers
Is Lisbon hot in August?
Warm rather than hot: in August, daytime highs in Lisbon average 24 °C and nights cool to about 18 °C.
Can you swim in Lisbon in August?
Only if you don't mind cold water: in August the sea averages just 18.6 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Lisbon in August?
It hardly ever rains.
Lisbon month by month
The whole year in LisbonAll destinations: PortugalWhere to go in AugustSea temperature in August
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0)