September Weather in Warsaw, United States

Last updated: June 24, 2025

In Warsaw, United States, the average temperature in September hovers around 18°C (65°F). Expect a minimum of 2°C (36°F) and a peak of 33°C (91°F) during this time. Precipitation is notable, with 139 mm (5.5 in) of rain spread over 10 days, contributing to an average humidity level of 81%. Enjoy the dynamic weather as it transforms the landscape!

September Temperature in Warsaw

In September in Warsaw, the average temperature is 18°C (65°F), with maximums reaching 33°C (91°F) and minimums dropping as low as 2°C (36°F). This makes Warsaw an ideal destination for travelers seeking a mix of comfortable days and cooler 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 18°C (65°F), with highs reaching up to 33°C (91°F) and lows dropping to around 2°C (36°F).

Data source: Temperature data for Warsaw generated using information from the Copernicus Climate Change Service.

September Precipitation in Warsaw

In Warsaw, in September, the total precipitation amount is 139 mm (5.5 in) accumulated over 10 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 139 mm (5.5 inches) of precipitation spread over approximately 10 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Warsaw

In Warsaw in September, humidity is 81%. With an average temperature of 18°C (65°F), this humidity feels like a thick blanket wrapping around you, making every step feel heavier and the air thick and sultry—a challenging environment for traveling.

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 81%, offering insight into how humid the weather typically is during this month.

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.

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.
	Temperature	Precipitation	Humidity	UV
January Weather	-9°C (17°F)	35 mm (1.4 inches)	87%	moderate
February Weather	-9°C (17°F)	39 mm (1.5 inches)	90%	moderate
March Weather	1°C (33°F)	65 mm (2.6 inches)	85%	moderate
April Weather	6°C (44°F)	89 mm (3.5 inches)	84%	very high
May Weather	15°C (59°F)	136 mm (5.3 inches)	78%	very high
June Weather	22°C (72°F)	114 mm (4.5 inches)	80%	very high
July Weather	23°C (74°F)	112 mm (4.4 inches)	81%	very high
August Weather	21°C (71°F)	136 mm (5.3 inches)	81%	very high
September Weather	18°C (65°F)	139 mm (5.5 inches)	81%	very high
October Weather	9°C (49°F)	91 mm (3.6 inches)	84%	moderate
November Weather	1°C (34°F)	37 mm (1.5 inches)	88%	moderate
December Weather	-4°C (25°F)	46 mm (1.8 inches)	84%	low