September · Portugal
Best time to visit Cascais in September Weather, crowds & prices
Weather in Cascais in September
Average temperature 20°C, 34 mm of rain, about 23 days with 6+ hours of sunshine and 82% humidity — based on the five most recent complete years of ERA5 data (2021–2025).
September score
8.2/10
Ranked #3 of 12 months
- Avg temp
- 20°C
- Rainfall
- 34 mm
- Humidity
- 82%
- Days with 6h+ sun
- 23
- Crowd Density
- Moderate Crowds
- Average Expenses
- $$$ · Peak Season Rates ($$$)
September in Cascais scores 8.2/10 for beach and coastal travel - one of the top 12-month picks (#3). Expect around 20°C, 34 mm of rain, and roughly 23 days with 6+ hours of sunshine this month.
Cascais pairs a walkable former fishing town with sheltered beaches, an Atlantic promenade, and the wilder coast toward Guincho.
September in Cascais — reliably good (3rd best month)
With 20°C (68°F) on average, September delivers classic beach weather: plenty of time in the water, with beach and boat plans rarely disrupted by cold.
With around 34 mm of rain, any showers tend to pass through rather than settle in; about 23 days with 6+ hours of sunshine and 12.2 hours of daylight fill the rest.
That is 8.2/10 on the same scale — 3rd of 12 months, versus 8.5/10 for the best month here.
Pack light clothing, swimwear and real sun protection.
Expect peak pricing, and crowds are moderate. You are paying the year's highest rates for the year's best conditions — book early or shift a few weeks either side.
Frequently asked
- What is the weather like in Cascais in September?
- In September, Cascais averages 20°C, 34 mm of rain, and about 23 days with 6+ hours of sunshine. Its climate-comfort score is 8.2/10.
- Is September a good time to visit Cascais?
- September earns a 8.2/10 climate-comfort score. Use the year-round chart to weigh the weather against your budget and crowd preferences.
- How much does it rain in Cascais in September?
- Expect about 34 mm of rain in September. Average humidity is 82% and there are about 23 days with 6+ hours of sunshine.
Curated in Cascais
Tickets & experiences
Things to do in Cascais
Cascais, Portugal. Live activities and tours from GetYourGuide, matched to this destination.