The highest day temperature in September 2025 was 81°F. The lowest night temperature was 52°F. The average values for day and night temperatures during September were 70.7°F и 61.5°F respectivly.

The average sea surface temperature in September 2025 for Itajai was 67.9°F. The maximum and minimum values were 66.4°F and 70.0°F respectively.

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

Precipitation total in September for Itajai is 1.3 in. It makes september one of the least rainy months of the year.

The average wind speed in September is 5.9 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 Itajai in September is 4.5 hours.