Weather in Cascais for September 2025
Until now, September 2025 in Cascais has been nearly identical to the historical average, with a temperature of 20.8 °C (showing only a slight deviation of 0.1 °C).
The forecast for the next days in Cascais predicts temperatures to be around 22 °C, close to the historical average.
In general, the average temperature in Cascais at the beginning of September is 20.6 °C. As the month progressed, temperatures tended to moderately rise, reaching an average of 21.3 °C by the end of September.
Cascais experiences moderate rainfall in September, with an average of 8 rainy days and a total precipitation of 28.4 mm.
Is September a good time to visit Cascais? check out the best time to travel to Cascais page.
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Cascais Weather September
Temperatures trend during September in Cascais
September weather in Cascais day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Overcast | 21° /17° | 0.1 mm | 5 | |
| 2 Sept. |  Sunny | 20° /17° | 0.1 mm | 5 | |
| 3 Sept. |  Partly cloudy | 21° /16° | 1.3 mm | 5 | |
| 4 Sept. |  Light rain | 21° /17° | 3.8 mm | 5 | |
| 5 Sept. | Partly cloudy | 20° /17° | 1.4 mm | 5 | |
| 6 Sept. |  Cloudy | 20° /17° | 0 mm | 5 | |
| 7 Sept. |  Patchy rain possible | 21° /17° | 1.9 mm | 5 | |
| 8 Sept. | Overcast | 20° /17° | 0 mm | 5 | |
| 9 Sept. | Partly cloudy | 21° /17° | 0.9 mm | 6 | |
| 10 Sept. | Patchy rain possible | 21° /18° | 0.2 mm | 5 | |
| 11 Sept. | Sunny | 21° /18° | 0 mm | 6 | |
| 12 Sept. | Sunny | 21° /17° | 0 mm | 6 | |
| 13 Sept. | Sunny | 21° /17° | 0 mm | 6 | |
| 14 Sept. | Sunny | 23° /18° | 0 mm | 6 | |
| 15 Sept. | Sunny | 23° /18° | 0 mm | 1.7 | |
| 16 Sept. | Sunny | 23° /17° | 0 mm | 1.6 | |
| 17 Sept. | Sunny | 23° /18° | 0 mm | 1.6 | |
| 18 Sept. | Sunny | 24° /20° | 0 mm | 1.5 | |
| 19 Sept. | Sunny | 23° /20° | 0.1 mm | 1.1 | |
| 20 Sept. | Patchy rain possible | 23° /20° | 0.4 mm | 5 | |
| 21 Sept. | Sunny | 21° /18° | 0 mm | 5 | |
| 22 Sept. | Partly cloudy | 20° /18° | 0 mm | 5 | |
| 23 Sept. | Partly cloudy | 20° /17° | 0 mm | 5 | |
| 24 Sept. | Sunny | 20° /17° | 0 mm | 5 | |
| 25 Sept. | Sunny | 20° /18° | 0 mm | 5 | |
| 26 Sept. | Partly cloudy | 20° /18° | 0 mm | 5 | |
| 27 Sept. | Patchy rain possible | 21° /19° | 1.4 mm | 4 | |
| 28 Sept. | Patchy rain possible | 22° /20° | 0.1 mm | 5 | |
| 29 Sept. | Sunny | 23° /17° | 0 mm | 6 | |
| 30 Sept. | Sunny | 23° /18° | 0 mm | 6 | |
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Cascais weather in September vs August vs October
| August | September | October | |
|---|---|---|---|
| Weather | Sunny | Sunny | Patchy rain possible |
| Temperatures | 23°/18° | 21°/18° | 20°/18° |
| Rainfall | 0 mm | 28 mm | 98 mm |
| Wind | 32 km/h | 25.1 km/h | 26.8 km/h |
| Humidity | 79% | 77% | 76% |
| Rainy days | 0 days | 8 days | 22 days |
| Dry days | 31 days | 22 days | 9 days |
Planning a trip to Cascais? Discover the best time to visit
Cascais in September - FAQ
Cascais water temperatures in September
The average water temperature of the Atlantic Ocean near Cascais in September is 17 °C. Temperatures remain fairly consistent throughout the month.
- What is the water temperature in Cascais in September?
- The average water temperature in Cascais in September is 17 °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.
What to pack to Cascais in September?
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.
- Clothing
- Layered Clothing: Light sweaters, long-sleeve shirts, light jackets, and comfortable pants
- Rain Gear: Lightweight, waterproof clothing
- Accessories
- Sunglasses: For sun protection
- Sun Hats: Wide-brimmed hats for sun protection in warm weather
- Umbrellas/Raincoats: For rainy days
September rainfall patterns in Cascais
UV exposure in Cascais during September
Quick links
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.