The highest day temperature in September 2026 was 81°F. The lowest night temperature was 66°F. The average values for day and night temperatures during September were 71.6°F и 68.5°F respectivly.

The average sea surface temperature in September 2026 for Cascais was 66.2°F. The maximum and minimum values were 63.4°F and 68.8°F respectively.

Most of the days in September are sunny but you can also expect cloudy and gloomy days.

Precipitation total in September for Cascais is 1.0 in. It makes september one of the least rainy months of the year.

The average wind speed in September is 11.8 mph. This value is relatively stable throughout the year.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Cascais in September is 10.0 hours.