Cascais 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: June – September
What is the weather like in Cascais in August?
In August, Cascais is warm: daytime highs average 26 °C, and nights cool down to about 19 °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 Cascais.
August compared
How the weather changes from July to September. Tap a month to open it.
| JulyJul | AugustAug | SeptemberSep | |
|---|---|---|---|
| Score | 79 | 81 | 76 |
| Day | 26° | 26° | 25° |
| Night | 18° | 19° | 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 min06:51 – 20:34
- 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
- 3 days30 °C or more
- Time zone
- UTC+1Europe/Lisbon
How the score comes together
- Temperatureweight 35 %100 %
- Seaweight 25 %23 %
- Sunshineweight 20 %100 %
- Few rainy daysweight 20 %100 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in August
- Wetsuit for longer swims
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
Cascais in August: quick answers
Is Cascais hot in August?
Warm rather than hot: in August, daytime highs in Cascais average 26 °C and nights cool to about 19 °C. On about 3 days the thermometer climbs to 30 °C or more.
Can you swim in Cascais 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 Cascais in August?
It hardly ever rains.
Cascais month by month
The whole year in CascaisAll 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)