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September Weather in Warsaw, United States

Last updated: June 24, 2025

In September, the average temperature in Warsaw, United States hovers around 20°C (69°F). Expect a refreshing range, with minimums dipping to 4°C (40°F) and maximums reaching up to 35°C (95°F). Be prepared for some rain too, as the area receives an average of 103 mm (4.0 in) over 9 days. With an average humidity of 77%, it’s a perfect blend of warmth and moisture for a delightful experience!

September Temperature in Warsaw

In September in Warsaw, the average temperature is 20°C (69°F). Maximums can reach 35°C (95°F), and minimums can be as low as 4°C (40°F). This weather makes Warsaw an ideal destination for travelers seeking both warmth and cool, refreshing evenings.

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 (69°F), with highs reaching up to 35°C (95°F) and lows dropping to around 4°C (40°F).
JanFebMarAprMayJunJulAugSepOctNovDec313442526371757368574236
Data source: Temperature data for Warsaw generated using information from the Copernicus Climate Change Service.
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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 103 mm (4.0 in) over the course 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 103 mm (4.0 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec87108108129126136116871031059798
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Warsaw

In Warsaw in September, humidity is 77%. With an average temperature of 20°C (69°F), this humidity feels like a sultry embrace, making travel comfortable yet slightly sticky, as the moist air clings to your skin with every step you take.

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 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%88%87%87%81%83%82%76%77%82%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.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098642
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-1°C (31°F)87 mm (3.4 inches)88%moderate
February Weather1°C (35°F)108 mm (4.2 inches)88%moderate
March Weather6°C (42°F)108 mm (4.3 inches)87%high
April Weather11°C (52°F)129 mm (5.1 inches)87%very high
May Weather17°C (63°F)126 mm (4.9 inches)81%very high
June Weather22°C (71°F)136 mm (5.4 inches)83%very high
July Weather24°C (76°F)116 mm (4.6 inches)82%very high
August Weather23°C (73°F)87 mm (3.4 inches)76%very high
September Weather20°C (69°F)103 mm (4.0 inches)77%very high
October Weather14°C (58°F)105 mm (4.1 inches)82%high
November Weather6°C (42°F)97 mm (3.8 inches)89%moderate
December Weather2°C (37°F)98 mm (3.9 inches)86%low

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