Best time to visit Cascais

Re-score for me — drag the dial — every chart recolours live for your heat & sea limits 27°C · sea 29°C
I'm comfortable up to 27°C feels-like
22° heat-averse 30° heat-loving

Default 27 °C is the upper edge of the Holiday Climate Index "ideal comfort" band (Scott, Rutty, Amelung & Tang, 2016). Above this, most warm-tourism travellers report measurable discomfort.

Sea feels bathtub at 29°C
26° strict 31° tolerant

Default 29 °C is the Beach Climate Index "bathtub" line (Morgan et al.) — where the sea stops being refreshing and starts feeling like a warm bath.

Saved to this browser. Changes update the strips below.
Sea temp cold <18° chilly 18–21° ideal 22–26° warm 27–28° bathtub 29–30° too warm ≥31°
Recent · 2020-2024
Interest Google Trends 2021-2025 searches, not arrivals (?)
Sea Nov 2022 – Dec 2024 (?)
Day · avg daily high (?)
Night · avg overnight low (?)
UV index · On a typical day around midday, UV is about this (?)
234678986422
On the sunniest 1 in 10 days, UV reaches this — and even higher
468953
PM2.5 air quality · on a typical day (?)
797767676768
On the worst 1 in 10 days, PM2.5 reaches this — and even higher
151614119109119111115
July 9/10 feels 22°C (−1°C vs 1991-2020) · HCI 94/100
Day 23° · Night 18° ☀ UV 8.8 (very high) 71% humidity 29 km/h wind 1 rain day (21h) 307h sun sea 17°C
Thermal 8
Sky 10
Rain 10
Wind 9

Higher = better, including rain & wind (green = "doesn't hurt the score", not "lots of it").

How is this scored? HCI / Steadman / CCI gate — full methodology and citations below.

Compare with another destination

Add as many as you like — stacked below the main strips above. Each row is just the recent-window score strip and (for beach destinations) sea-temperature strip.

Tours in Cascais

7 top-rated tours via Viator. Booking links earn this site a commission at no cost to you. Map locations are approximate (centred on Cascais).

  1. 1Cascais Private Luxury Sunset 2h Cruise with a drink4.97★ (30)2hfrom $614🔥 Selling fast
  2. 2Lisbon Hike on the Edge of Europe5.00★ (19)4hfrom $59🔥 Selling fast
  3. 3Cascais coast: Dolphin watching5.00★ (23)2hfrom $76🔥 Selling fast
  4. 4Surf Lesson on Praia de Carcavelos4.81★ (85)2hfrom $47🔥 Selling fast
  5. 5Dolphin Watching Experience in Cascais5.00★ (1)2hfrom $76🔥 Selling fast
  6. 6Lisbon Rock Climbing Experience5.00★ (19)4hfrom $70🔥 Selling fast
  7. 7Cascais Scavenger Hunt and Sights Self-Guided Tour4.89★ (9)2hfrom $4

Last refreshed 2026-06-20.

Similar climatesFunchal91% · Lisbon90% · Capri89%

Other destinations with the most-alike year-round climate to Cascais (apparent temperature, rain hours, sunshine — matched within the same trip-profile). The ±N chip compares each match's typical score for the current month against Cascais's. Based on the 2020-2024 climatology, not this year's actual weather.

Month-by-month

Month Temp °C Feels °C Rain days Rain h Rain h/day Humidity Wind km/h Sun h UV Interest Score
Jan 10–15 12 10 129 12.9 74% 23 178 2 Quiet 7
Feb 11–16 14 9 111 12.3 73% 24 178 3 Quiet 7
Mar 12–17 14 11 143 13.0 71% 26 222 4 Quiet 7
Apr 13–18 16 11 151 13.7 74% 25 247 6 Quiet 7
May 15–20 18 8 95 11.9 71% 27 287 7 Quiet 8
Jun 16–21 19 8 100 12.5 73% 27 293 8 Quiet 8
Jul 18–23 22 1 21 21.0 71% 29 307 9 Moderate 9
Aug 18–23 22 1 22 22.0 74% 29 279 8 Peak 9
Sep 18–22 22 7 92 13.1 73% 24 240 6 Moderate 9
Oct 16–21 20 12 151 12.6 76% 24 201 4 Moderate 7
Nov 14–18 17 10 125 12.5 76% 23 171 2 Busy 7
Dec 12–16 14 13 168 12.9 78% 25 168 2 Busy 6

UV Index in Cascais by Month

UV index in Cascais peaks at 9 (very high) in July, dropping to 2 (low) in December. June, July, August reach very high or extreme levels — apply SPF 50+, wear a hat and protective clothing, and limit direct sun between 11:00 and 17:00.

Best months in detail

July

9/10

18–23°C (feels 22°C) · 1 rain days (21h) · 307 sun hours · 71% humidity · Moderate crowd · UV 9 (very high)

August

9/10

18–23°C · 1 rain days (22h) · 279 sun hours · 74% humidity · Peak crowd · UV 8 (very high)

September

9/10

18–22°C · 7 rain days (92h) · 240 sun hours · 73% humidity · Moderate crowd · UV 6 (high)

Every month

Show the other 9 months in detail

January

7/10

10–15°C (feels 12°C) · 10 rain days (129h) · 178 sun hours · 74% humidity · Quiet crowd · UV 2 (low)

February

7/10

11–16°C (feels 14°C) · 9 rain days (111h) · 178 sun hours · 73% humidity · Quiet crowd · UV 3 (low) · sunniest 1 in 10 days reach 4 (moderate)

March

7/10

12–17°C (feels 14°C) · 11 rain days (143h) · 222 sun hours · 71% humidity · Quiet crowd · UV 4 (moderate) · sunniest 1 in 10 days reach 6 (high)

April

7/10

13–18°C (feels 16°C) · 11 rain days (151h) · 247 sun hours · 74% humidity · Quiet crowd · UV 6 (high) · sunniest 1 in 10 days reach 8 (high)

May

8/10

15–20°C (feels 18°C) · 8 rain days (95h) · 287 sun hours · 71% humidity · Quiet crowd · UV 7 (high) · sunniest 1 in 10 days reach 9 (very high)

June

8/10

16–21°C (feels 19°C) · 8 rain days (100h) · 293 sun hours · 73% humidity · Quiet crowd · UV 8 (very high)

October

7/10

16–21°C · 12 rain days (151h) · 201 sun hours · 76% humidity · Moderate crowd · UV 4 (moderate) · sunniest 1 in 10 days reach 5 (moderate)

November

7/10

14–18°C (feels 17°C) · 10 rain days (125h) · 171 sun hours · 76% humidity · Busy crowd · UV 2 (low) · sunniest 1 in 10 days reach 3 (moderate)

December

6/10

12–16°C (feels 14°C) · 13 rain days (168h) · 168 sun hours · 78% humidity · Busy crowd · UV 2 (low)

Frequently asked questions about visiting Cascais

When is the best time to visit Cascais?

July is the highest-scoring month (9/10 on the Holiday Climate Index). Typical conditions: 18–23°C (1 rainy day). The top three months by score are July, August, September.

What is the worst time to visit Cascais?

December is the lowest-scoring month (6/10). Typical conditions: 12–16°C (13 rainy days).

When are crowds lowest in Cascais?

Search-interest seasonality (Google Trends 2021-2025) is lowest in January and peaks in August. Interest tracks both in-trip visitors and lead-time planners, so treat it as a "destination is on people's minds" signal rather than literal arrivals.

Which months in Cascais have good weather but fewer tourists?

July (climate 9/10, crowd index 41) and May (climate 8/10, crowd index 17) — shoulder months with above-average climate and below-median search-interest. Often the best value-for-weather trade.

What is the UV index in Cascais by month?

UV peaks at 9 (very high) in July and is lowest in December at 2 (low). Monthly peak values: Jan 2, Feb 3, Mar 4, Apr 6, May 7, Jun 8, Jul 9, Aug 8, Sep 6, Oct 4, Nov 2, Dec 2. June, July, August reach very high or extreme levels — apply SPF 50+, wear a hat and protective clothing, and limit direct sun between 11:00 and 17:00.

What is the UV index in Cascais in July?

July is the peak UV month in Cascais, with a daily-peak UV index of 9 (very high). At this level, sunburn can occur in under 20 minutes on unprotected fair skin. Apply SPF 50+, wear protective clothing and a hat, and avoid direct midday sun (11:00–17:00).

How high can UV get in Cascais on the sunniest days?

Most days look like the monthly average, but on the sunniest ~1 in 10 days UV climbs higher than the mean suggests. May is the worst case: typical days average UV 7 (high), but the top 10% of days reach UV 9 (very high) — and even higher. Months where the sunniest days routinely exceed the typical reading: February, March, April, May, October, November. Plan sun protection for the worst case, not the average.

Is air quality in Cascais bad for travelers?

PM2.5 (fine-particle pollution) exceeds the WHO sensitive-group guideline (15 µg/m³) in 1 month: February. The worst month is February with a typical-day mean of 9 µg/m³ (fair); on the worst 10% of days PM2.5 reaches 16 µg/m³ (unhealthy for sensitive) and higher. People with asthma, heart conditions, or sensitive children may want to avoid these months or limit outdoor activity. Source: CAMS via Open-Meteo.