Portugal
Cascais in September: weather, sea & travel advice
This month's data profile
Strong month under the current formula
Cascais in September is climatically well suited to city breaks, active holidays and hiking, family holidays and beach holidays. The average daily high is around 22 °C, and the sea is about 19 °C. With about 5 rainy days it is dry.
Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.
Rank among 12 monthly averages
81/100 · #3
Warmth
#3
Dryness
#4
Sun
#6
Sea warmth
#1
Published best categories: Overall, Beach, City break, Family
Cascais · SeptemberPhoto: Terry Kearney from liverpool, merseyside · CC0Climate facts
- Average high
- 22 °C
- Average low
- 18 °C
- Sea
- 19 °C
- Rainy days (est.)
- 5 rainy days (est.)
- Sun (est.)
- 7 h/day
- Humidity
- 81 %
Climate evidence with direct month comparison
The highlighted row is the selected month. Precipitation total and rainy days are separate monthly averages.
| Month | Avg high °C | Avg low °C | Rainy days (est.) | Precipitation mm | Sun h/day (est.) | Humidity % | Wind m/s | Sea °C | Score |
|---|---|---|---|---|---|---|---|---|---|
| August | 23 | 18 | 1 | 5 | 8.3 | 81 | 4.5 | 19 | 84 |
| September (selected) | 22 | 18 | 5 | 28 | 6.6 | 81 | 4.0 | 19 | 81 |
| October | 21 | 17 | 10 | 76 | 4.5 | 81 | 4.2 | 18 | 66 |
How do the previous and next months compare?
Baseline: September (81/100)
Positive and negative values show the change from the selected month.
| Score Δ | Average high Δ | Average low Δ | Rainy days Δ | Rain Δ | Sun Δ | Humidity Δ | Wind Δ | Sea Δ | |
|---|---|---|---|---|---|---|---|---|---|
| August | +3 | +0.9 °C | +0.4 °C | -4 | -22.7 mm | +1.7 h | -0.4 % | +0.5 m/s | -0.1 °C |
| October | -15 | -1.8 °C | -1.3 °C | +5.2 | +48.3 mm | -2.1 h | +0.5 % | +0.2 m/s | -0.5 °C |
All twelve months in context
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Frequently asked questions
How warm is Cascais in September?
The average daily high is around 22 °C, with an average daily low of about 18 °C.
Can you swim in Cascais in September?
The sea is about 19 °C (refreshing).
Does it rain a lot in Cascais in September?
The curated estimate is about 5 rainy days per month, not a directly measured long-term average. Total precipitation averages around 28 mm for the month. A rainy day does not mean all-day rain.
When is the best time to visit Cascais?
By the climate score, June, July, August and September are the strongest months for Cascais. For a beach trip: June, July, August and September. September is one of them.