Month guide · Cascais, Portugal
Cascais in September: weather and what to expect
September highs in Cascais are now 0.9°C warmer than in 1991-2000. The sea is still cool, around 18°C. In September, Cascais averages highs of 23°C and lows of 18°C, with about 4 rainy days and 31 mm of rain. Our rules rate it good for walking and cycling. Crowds in the Lisbon area are high.
Is September a good time to visit?
Good for
- Walking and cyclingHighs of 23°C with about 4 rainy days
Not ideal for
Nothing stands out as a weaker fit.
Daily highs through September
Town-level · ERA5-Land 1991-2020Highs fall about 2°C over the month. Nights below 15°C in about 1 in 3.
September in detail
Town-level · ERA5-LandCrowds, holidays and daylight
Public holidays in September 2027
No national or regional public holidays.
Local (municipal) holidays are not included.
Warmer in September
Where is warm in September →| Place | High | Rain days | From Cascais |
|---|---|---|---|
| Marinhais, Oeste e Vale do Tejo | 28°C | 5 | 73 km |
| Benavente, Oeste e Vale do Tejo | 28°C | 5 | 62 km |
| Salvaterra de Magos, Oeste e Vale do Tejo | 28°C | 5 | 66 km |
| Samora Correia, Oeste e Vale do Tejo | 27°C | 5 | 55 km |
| Pontével, Oeste e Vale do Tejo | 27°C | 5 | 71 km |
The nearest towns with a warmer September. Distances are in a straight line.
How September is changing
Town-level · ERA5-LandSeptember highs are 0.9°C warmer than in 1991-2000, and September rainfall is down about 20% (2016-2025 against 1991-2000). Days above 25°C in September went from 4.8 to 6.9 a year on average.
Questions about Cascais in September
Is September a good time to visit Cascais?
Our rules rate September good for walking and cycling (highs of 23°C with about 4 rainy days).
How warm is Cascais in September?
Average highs are 23°C and lows 18°C. August averages 25°C and October 21°C.
Does it rain much in Cascais in September?
About 4 days have at least 1 mm of rain, with 31 mm in total over the month.
Is Cascais busy in September?
In September 2025, nights booked through online platforms in the Lisbon area were about 75% of the busiest month, which we count as high. The figure is for the whole region and leaves out hotels.
How long are the days in Cascais in September?
About 12 h 30 min from sunrise to sunset in the middle of the month.
Sources
Climate: ERA5-Land, Copernicus Climate Change Service (C3S) Climate Data Store, contains modified Copernicus information (CC BY 4.0). Crowds: Eurostat, nights spent in short-stay accommodation booked through online platforms (tour_ce_omn12) (CC BY 4.0). Place names and populations: GeoNames (CC BY 4.0). Climate averages cover 1991-2020. Daylight: calculated from the town's coordinates. Full methodology