Warsaw Weather in September

The climate in Warsaw during September can be summarized as mild and a little damp.

September is in the fall / autumn in Warsaw and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 24°C (75°F), whilst at night 11°C (52°F) is normal.

On average September is the 6th wettest month of the year in Warsaw with around 84mm 3.3 inches of rain making it a a little damp time to visit. This rainfall is typically spread over 9 days, although this may vary considerably.

On the flip side this corresponds to an average of 8.7 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 Warsaw in September 2025.