The highest day temperature in September 2026 was 98°F. The lowest night temperature was 61°F. The average values for day and night temperatures during September were 86.1°F и 69.7°F respectivly.

The average sea surface temperature in September 2026 for Porto was 64.6°F. The maximum and minimum values were 59.0°F and 71.0°F respectively.

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

Precipitation total in September for Porto is 1.7 in. It makes september one of the least rainy months of the year.

The average wind speed in September is 6.8 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 Porto in September is 9.5 hours.