Cascais Weather in September
September is one of the perfect months to visit Cascais, with daytime temperatures of 22°C (72°F) and lows of 18°C (64°F) at night. Some rainfall is typical for this time of year.
Rainfall in Cascais in September
You can typically expect 6 days of rain this month, averaging around 31 mm (1.2 in). Rain is scarce this month and when it does fall, it tends to be light. Unlikely to disrupt plans significantly.
Temperature in Cascais in September
The perfect temperature in Cascais in September makes it a solid month to visit, with 22°C (72°F) during the day and 18°C (64°F) at night. This creates a mild day-to-night pattern that is generally easy to manage with the right clothing. At 18°C (64°F) overnight, it can feel quite a bit cooler after dark. Worth packing something warmer for evenings, but the cooler temperatures are ideal for sleeping.
Sunshine in Cascais in September
There are approximately 278 hours of sunshine this month, resulting in mostly clear days.If you're inclined towards comfortable temperatures and drier conditions, September is a good time to visit Cascais.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Portugal, check out our Cascais's climate page.
Cascais Temperature in September
Min Temperature
18°C (64°F)
Max Temperature
22°C (72°F)
Chance of Rain
20%
Precipitation
31 mm (1.2 in)
Rainy days
6 days
Humidity
75%
Sunshine
278 hours
Percentage Sunshine
75%
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Cascais typically stay consistent throughout September, with daily highs averaging around 22°C (72°F). Nights are pleasant, with lows typically ranging from 16°C (61°F) to 18°C (64°F).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Cascais in September
Browse day-by-day weather records for Cascais spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Cascais historical weather extremes in September
The extremes listed below come from historical weather data collected in Cascais from 1976 through 2025.
- On September 4, 2006, temperatures climbed to 39°C (102°F), marking the warmest September day on record.
- The coldest September day was on September 26, 1992, with a maximum of 18°C (64°F).
- The coldest night in September in Cascais was on September 21, 2000, with a minimum of 11°C (52°F).
Best Places in Portugal in September
Find out more about the weather in Portugal and which places have the best travel conditions in this month. See all of Portugal in September →
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What to Wear in Cascais in September
Pleasant temperatures in September mean you can pack light but flexibel pieces. Think cotton t-shirts, comfortable walking shorts, and one warmer layer for evenings. A light sweater or denim jacket works well. Pack a light rain jacket or compact umbrella for occasional showers. Don't forget sun protection, sunglasses, sunscreen, and a hat. These are all good ideas with this much sunshine.What To Do in Cascais in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Portugal, check out our Cascais's climate page.
Temperature Rainfall Sunshine Humidity
See the full Cascais climate overview or explore weather in Portugal.
