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Cascais weather forecast and sea temperature

Right now in Cascais: clear skies, 21°C, feels like 21°C.

Expect a mostly clear week in Cascais, with temperatures staying fairly steady between 16°C and 32°C.

Daytime highs this week are about 2°C above the August average of 23°C.

Sunrise: 07:03 · Sunset: 20:14 · Day length: 13h 11m

Cascais sea temperature today

Sea water: 20.5°C, cooling to around 18°C over the coming days

Wave height: 2.4m (min 1.1m on 2026-09-03, max 2.4m on 2026-08-28)

Cascais water temperature for the next 7 days · Sea temperature along the whole coast

Next 24 hours

20:00 21°
21:00 20°
22:00 20°
23:00 19°
00:00 19°
01:00 19°
02:00 19°
03:00 19°
04:00 18°
05:00 18°
06:00 18°
07:00 18°
08:00 18°
09:00 20°
10:00 21°
11:00 22°
12:00 23°
13:00 23°
14:00 24°
15:00 24°
16:00 24°
17:00 23°
18:00 23°
19:00 22°
  1. Fri 28/08 clear skies 23°16°
  2. Sat 29/08 sunny and clear 24°18°
  3. Sun 30/08 bright and clear 25°20°
  4. Mon 31/08 overcast 25°19°
  5. Tue 01/09 sunny and clear 23°19°
  6. Wed 02/09 bright and clear 24°19°
  7. Thu 03/09 clear skies 32°18°

Cascais enjoys one of the gentlest climates on the Portuguese coast. Its beaches face south, sheltered from the prevailing north wind by the Sintra hills behind the town, so afternoons here are calmer and sunnier than on the exposed west coast just a few kilometres away. Summer days usually reach 26–28 °C with a light sea breeze taking the edge off the heat.

The ocean itself stays firmly Atlantic: even at the end of summer the water rarely passes 18–19 °C, refreshing rather than tropical. Winters are mild and often sunny, with daytime temperatures around 15–16 °C that keep the seafront promenade busy year round. Rain falls mostly between October and February in short Atlantic episodes.

Climate through the year

Month Min (°C) Max (°C) Rainy days
January 10.5 15.0 10.8
February 10.9 15.7 8.5
March 11.5 16.2 11.7
April 12.9 17.5 12.4
May 14.8 19.4 7.9
June 16.5 20.9 7.3
July 17.6 22.5 3.0
August 18.0 23.0 1.5
September 17.5 22.6 4.5
October 16.3 21.1 10.2
November 13.4 17.6 11.8
December 11.6 15.8 11.7

Going by Cascais's own averages, August is both the warmest and the most balanced month: highs near 23 °C and about 2 rainy days. The wettest is April with 12 rainy days.

Averages for 2016–2025. A rainy day is one with at least 1 mm of precipitation.

How warm is the sea in Cascais?

Cooler than most visitors expect. The water peaks at around 18–19 °C in August and September and sits near 15 °C in winter, because this stretch of Atlantic never really warms up.

Why is Guincho so windy when the town beaches are calm?

Guincho faces west, fully exposed to the nortada, the northerly wind that blows on most summer afternoons. The town beaches face south and sit in the shelter of the Sintra hills, so the same wind passes mostly overhead.

Is Cascais worth visiting in winter?

Yes. Winter days are often sunny at 15–16 °C, good for walking the coastal path to Estoril or towards Guincho. Rain comes in short spells rather than settled grey weeks.