The highest day temperature in September 2025 was 82°F. The lowest night temperature was 54°F. The average values for day and night temperatures during September were 71.0°F и 63.1°F respectivly.

The average sea surface temperature in September 2025 for Giresun was 77.7°F. The maximum and minimum values were 72.0°F and 82.8°F respectively.

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

Precipitation total in September for Giresun is 1.8 in. It makes september one of the least rainy months of the year.

The average wind speed in September is 5.7 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 Giresun in September is 8.3 hours.