The highest day temperature in August 2025 was 91°F. The lowest night temperature was 60°F. The average values for day and night temperatures during August were 77.5°F и 66.4°F respectivly.

The average sea surface temperature in August 2025 for Niteroi was 73.5°F. The maximum and minimum values were 71.4°F and 76.6°F respectively.

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

Precipitation total in August for Niteroi is 1.4 in.

The average wind speed in August is 6.5 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 Niteroi in August is 7.9 hours.