Cascais weather in May
Temperature, sea and sunshine in May: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in May
Fair
Best time to visit: June – September
What is the weather like in Cascais in May?
In May, Cascais is mild: daytime highs average 21 °C, and nights cool down to about 14 °C. The sea averages 16.5 °C – swimming is only for the hardy. With around 10 hours of sunshine a day, there is plenty of sun. Rain falls on about 6 days, adding up to 38 mm. All in all, May is a so-so month for a holiday in Cascais.
May compared
How the weather changes from April to June. Tap a month to open it.
More details for May
- Daylight
- 14 h 15 min06:26 – 20:41
- UV index
- 9 · very highclear sky, noon (estimate)
- Muggy days
- 0 daysdew point 18 °C or more
- Wind
- 24 km/haverage daily peak
- Cloud cover
- 44 %on average
- Hot days
- 0 days30 °C or more
- Time zone
- UTC+1Europe/Lisbon
How the score comes together
- Temperatureweight 35 %28 %
- Seaweight 25 %0 %
- Sunshineweight 20 %100 %
- Few rainy daysweight 20 %89 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in May
- Wetsuit for longer swims
- Sunscreen
- Sunglasses & sun hat
- A jumper for the evenings
Cascais in May: quick answers
Is Cascais hot in May?
No. In May, Cascais is mild: daytime highs average 21 °C and nights drop to about 14 °C.
Can you swim in Cascais in May?
Only if you don't mind cold water: in May the sea averages just 16.5 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Cascais in May?
Rain falls on about 6 days, adding up to 38 mm.
Cascais month by month
The whole year in CascaisAll destinations: Portugal
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, GeoNames (CC BY 4.0)