nomadseason

September Weather in Warsaw, United States

Last updated: June 24, 2025

In Warsaw, United States, the average temperature in September hovers around 20°C (68°F). While you can expect some warmth, the range can vary significantly, dipping to a chilly 4°C (39°F) and soaring to a sweltering 33°C (91°F). Be prepared for 74 mm (2.9 in) of precipitation spread over 9 days, contributing to an average humidity level of 78%.

September Temperature in Warsaw

In September in Warsaw, the average temperature is 20°C (68°F). Maximums can reach 33°C (91°F) and minimums can be as low as 4°C (39°F). This makes Warsaw a great destination for travelers looking to enjoy a mild climate with a variety of temperature experiences.

September Weather in Warsaw: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Warsaw, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Warsaw, September typically has an average temperature of 20°C (68°F), with highs reaching up to 33°C (91°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec282940496272757367554034
Data source: Temperature data for Warsaw generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Warsaw

In Warsaw in September, the precipitation amount is 74 mm (2.9 in), which occurs over a span of 9 days.

September Precipitation Trends in Warsaw

The chart displays monthly precipitation patterns in Warsaw, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Warsaw, September typically receives around 74 mm (2.9 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec737710597134113116104741138162
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Warsaw

In Warsaw in September humidity is 78%. With an average temperature of 20°C (68°F), this humidity feels like a warm, enveloping blanket that makes exploring the sights a bit sticky, so travelers should stay hydrated and take frequent breaks in the shade.

September Average Humidity in Warsaw

This chart illustrates the average monthly humidity levels in Warsaw, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Warsaw is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%86%87%81%82%81%79%78%81%89%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Warsaw

In Warsaw in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Warsaw.

Maximum UV Index Levels in Warsaw for September

The chart shows the monthly maximum UV Index (UVI) for Warsaw in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Warsaw typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35699101098642
Data source: Warsaw September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How September Weather in Warsaw Compares to Other Months

Weather in Warsaw varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Warsaw, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Warsaw, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (28°F)73 mm (2.9 inches)85%moderate
February Weather-1°C (30°F)77 mm (3.0 inches)85%moderate
March Weather4°C (40°F)105 mm (4.1 inches)86%high
April Weather9°C (49°F)97 mm (3.8 inches)87%very high
May Weather16°C (62°F)134 mm (5.3 inches)81%very high
June Weather22°C (72°F)113 mm (4.4 inches)82%very high
July Weather24°C (76°F)116 mm (4.6 inches)81%very high
August Weather23°C (73°F)103 mm (4.1 inches)79%very high
September Weather20°C (68°F)74 mm (2.9 inches)78%very high
October Weather13°C (56°F)113 mm (4.5 inches)81%high
November Weather5°C (40°F)80 mm (3.2 inches)89%moderate
December Weather1°C (34°F)62 mm (2.5 inches)86%low

Compare Warsaw's Climate with Cities Worldwide