The climate in Koszalin during September can be summarized as mild and reasonably dry.
September is in the fall / autumn in Koszalin and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 18°C (64°F), whilst at night 10°C (50°F) is normal.
| Daytime temperature | 17.6°C 63.7°F |
|---|---|
| Nightly temperature | 10°C 50°F |
| Average temperature | 13.8°C 56.8°F |
| Daily sunshine | 5 hrs |
| Avg rainfall | 78 mm 3.1 ins |
| Rainy days | 15 days |
| Sea temperature | 15.8°C 60.4°F |
| Humidity | 82% |
| Windspeed | 14.8kph 9 mph |
On average September is the 2nd wettest month of the year in Koszalin with around 78mm 3.1 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 15 days, although this may vary considerably.
On the flip side this corresponds to an average of 5 hours of sunshine per day.
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Koszalin in September 2025.
Best places to visit in September
| Hottest month: | July | 21.6°C 70.9°F |
|---|---|---|
| Driest month: | February | 29mm 1.1ins |
| Sunniest month: | May | 8.3hrs |
| Coldest month: | January | 0.2°C 32.4°F |
| Wettest month: | July | 89mm 3.5ins |