September Weather in Warsaw, United States

Last updated: June 24, 2025

In September, the average temperature in Warsaw, United States hovers around 21°C (71°F). Expect a range from a cool 6°C (43°F) at night to a warm 35°C (95°F) during the day. During this month, precipitation averages 93 mm (3.7 in) over approximately 7 days, coupled with a high average humidity of 78%.

September Temperature in Warsaw

In September in Warsaw, the average temperature is 21°C (71°F). Maximum temperatures can reach 35°C (95°F), while minimums can drop as low as 6°C (43°F). Overall, it's a great time to explore Warsaw with warm days and cooler nights, perfect for outdoor adventures.

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 21°C (71°F), with highs reaching up to 35°C (95°F) and lows dropping to around 6°C (43°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 precipitation amount is 93 mm (3.7 in) over the course of 7 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 93 mm (3.7 inches) of precipitation spread over approximately 7 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 78%. With an average temperature of 21°C (71°F), this humidity feels like a warm blanket wrapped around you, making travel a bit more challenging as it can lead to a sticky, heavy sensation, dampening the enjoyment of outdoor activities.

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.

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	-2°C (28°F)	57 mm (2.3 inches)	81%	moderate
February Weather	-1°C (30°F)	57 mm (2.3 inches)	81%	moderate
March Weather	6°C (43°F)	107 mm (4.2 inches)	81%	high
April Weather	11°C (52°F)	99 mm (3.9 inches)	82%	very high
May Weather	18°C (65°F)	172 mm (6.8 inches)	78%	very high
June Weather	24°C (76°F)	108 mm (4.2 inches)	81%	extreme
July Weather	26°C (79°F)	88 mm (3.5 inches)	79%	very high
August Weather	24°C (76°F)	91 mm (3.6 inches)	77%	very high
September Weather	21°C (71°F)	93 mm (3.7 inches)	78%	very high
October Weather	13°C (56°F)	110 mm (4.3 inches)	78%	high
November Weather	5°C (42°F)	50 mm (2.0 inches)	87%	moderate
December Weather	2°C (35°F)	41 mm (1.6 inches)	84%	low