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Weather in Cascais for September 2026

Your guide to Cascais weather in September - trends and predictions

    Official Weather Alert ⚠️

  • Yellow High Temperature Warning - See hour by hour.

    • Temperatures

  • So far, September 2026 in Cascais is slightly warmer than the historical average by 0.6 °C.

  • The forecast for the next days in Cascais predicts temperatures to be around 20 °C, close to the historical average.

  • In general, the average temperature in Cascais at the beginning of September is 21.1 °C. As the month progressed, temperatures tended to moderately fall, reaching an average of 19.4 °C by the end of September.

    • Rain 🌧️

  • Cascais experiences moderate rainfall in September, with an average of 8 rainy days and a total precipitation of 21.9 mm.

    • More

  • Is September a good time to visit Cascais? check out the best time to travel to Cascais page.

  • New! Chat with our AI weatherman - it’s amazing and free.

Average dry days
22
Dry days
Average rainy days
8
Rainy days
Average snowy days
0
Snow days
Average temperatures
21°/17°
Temperatures
Average wind speed
27 km/h
Avg max wind
Average humidity
76 %
Avg humidity

Cascais Weather September

Move between months or click on a day
August
October
Sun.Mon.Tue.Wed.Thu.Fri.Sat.
1
Overcast
20°
2
Sunny
20°
3
Partly cloudy
23°
4
Overcast
23°
5
Partly cloudy
21°
6
Sunny
20°
7
Sunny
21°
8
Sunny
20°
9
Patchy rain possible
21°
10
Patchy rain possible
21°
11
Sunny
22°
12
Sunny
23°
13
Sunny
23°
14
Sunny
23°
15
Partly cloudy
22°
16
Sunny
22°
17
Light rain shower
23°
18
Partly cloudy
22°
19
Partly cloudy
22°
20
Patchy rain possible
21°
21
Weather Alert Sunny
23°
22
Sunny
22°
23
Sunny
22°
24
Sunny
21°
25
Sunny
20°
26
Overcast
19°
27
Overcast
19°
28
Sunny
19°
29
Sunny
19°
30
Overcast
19°

Temperatures trend during September in Cascais

See the weather trend as well as the moving average line

September weather in Cascais day by day

Click on a date for more information
August October
Date Weather Temperatures Rain UV More
1 Sept. Overcast
Overcast
 20° /17° 0.1 mm 6
2 Sept. Sunny
Sunny
 20° /17° 0.1 mm 6
3 Sept. Partly cloudy
Partly cloudy
 23° /17° 1 mm 6
4 Sept. Overcast
Overcast
 23° /17° 2.8 mm 5
5 Sept. Partly cloudy
Partly cloudy
 21° /17° 1.1 mm 6
6 Sept. Sunny
Sunny
 20° /17° 0 mm 6
7 Sept. Sunny
Sunny
 21° /18° 1.4 mm 6
8 Sept. Sunny
Sunny
 20° /17° 0 mm 5
9 Sept. Patchy rain possible
Patchy rain possible
 21° /17° 0.8 mm 6
10 Sept. Patchy rain possible
Patchy rain possible
 21° /18° 0.1 mm 6
11 Sept. Sunny
Sunny
 22° /18° 0 mm 6
12 Sept. Sunny
Sunny
 23° /18° 0 mm 6
13 Sept. Sunny
Sunny
 23° /18° 0 mm 6
14 Sept. Sunny
Sunny
 23° /19° 0 mm 6
15 Sept. Partly cloudy
Partly cloudy
 22° /18° 0 mm 6
16 Sept. Sunny
Sunny
 22° /18° 2.3 mm 6
17 Sept. Light rain shower
Light rain shower
 23° /18° 4 mm 6
18 Sept. Partly cloudy
Partly cloudy
 22° /17° 0.1 mm 6
19 Sept. Partly cloudy
Partly cloudy
 22° /17° 0 mm 6
20 Sept. Patchy rain possible
Patchy rain possible
 21° /17° 0.3 mm 5
21 Sept. Sunny
Sunny
 23° /20° 0 mm 6.5
22 Sept. Sunny
Sunny
 22° /19° 0 mm 6.5
23 Sept. Sunny
Sunny
 22° /19° 0 mm 6.1
24 Sept. Sunny
Sunny
 21° /19° 0 mm 6.1
25 Sept. Sunny
Sunny
 20° /18° 0 mm 5.8
26 Sept. Overcast
Overcast
 19° /18° 0 mm 5
27 Sept. Overcast
Overcast
 19° /18° 0 mm 5
28 Sept. Sunny
Sunny
 19° /18° 0.1 mm 5
29 Sept. Sunny
Sunny
 19° /18° 0 mm 5
30 Sept. Overcast
Overcast
 19° /17° 0 mm 4
Next
Important Notice
Our weather forecast for Cascais in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Cascais forecast closer to your planned date for the most up-to-date weather information.
Change Month
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Cascais weather in September vs August vs October

Compare September weather in Cascais with the previous and following months. See how temperature, rainfall, wind, and other conditions change throughout the year to help you plan your visit.
AugustSeptemberOctober
WeatherSunny
Sunny
Sunny
Sunny
Patchy rain possible
Patchy rain possible
Temperatures23°/18°21°/17°20°/18°
Rainfall0 mm22 mm77 mm
Wind30 km/h26.6 km/h24.9 km/h
Humidity79%76%76%
Rainy days0 days8 days20 days
Dry days31 days22 days11 days

Planning a trip to Cascais? Discover the best time to visit

Cascais in September - FAQ

What are the expected maximum and minimum temperatures in Cascais during September?
During September, expect a variety of temperatures with highs around 21° and lows near 17°, suitable for diverse activities and preferences.

How much rainfall should be expected in Cascais during September?
In September, Cascais can expect light to moderate rainfall, totaling 21.9 mm across approximately 8 days. Occasional showers are possible, and planning ahead for them could be helpful.

What are the typical wind conditions in Cascais during September?
The average wind speed in Cascais during September is 27 km/h, suggesting breezy to windy conditions, depending on your activities.

Cascais water temperatures in September

The average water temperature of the Atlantic Ocean near Cascais in September is 17.2 °C. At the beginning of September temperatures are around 17.4 °C; by the end of the month they get a bit cooler and reach 16.7 °C.

What is the water temperature in Cascais in September?
The average water temperature in Cascais in September is 17.2 °C.
Can you swim in Cascais in September?
Brisk: quick dips and active swimming are fine, but pack a 2–3 mm spring suit if you plan longer sessions or early-morning outings.

September rainfall patterns in Cascais

Explore the daily rainfall trends and prepare for Cascaiss September weather 💧
Typically, Cascais has 8 rainy days in September with a total of 21.9 mm of rainfall.

UV exposure in Cascais during September

Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️

What to pack to Cascais in September?

⛅ Mild · highs around 21 °C, occasional showers

As you prepare for your trip to Cascais in September, it's important to consider the typical weather patterns for the time of year. Below is a carefully tailored packing list to ensure that your time in Cascais, during September, is comfortable and enjoyable, regardless of the weather conditions.

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Location coordinates Where is Cascais?

Get accurate weather forecasts for Cascais, located at latitude 38.697 and longitude -9.421. Stay updated with localized weather information tailored for Cascais.

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