September Weather in Rosemont, United States

Last updated: June 24, 2025

In Rosemont, United States, the average temperature in September is a pleasant 23°C (73°F). However, temperatures can vary significantly, with minimums dipping to 8°C (47°F) and maximums soaring up to 43°C (109°F). You can expect very little rain, with an average precipitation of only 3 mm (0.1 in) over 0 days. The atmosphere is relatively dry, featuring an average humidity of 44%.

September Temperature in Rosemont

In September in Rosemont, the average temperature is 23°C (73°F), with maximums reaching up to 43°C (109°F) and minimums dropping as low as 8°C (47°F). Be prepared for a wide temperature range when planning your travel itinerary.

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

The chart illustrates September temperature patterns in Rosemont, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Rosemont, September typically has an average temperature of 23°C (73°F), with highs reaching up to 43°C (109°F) and lows dropping to around 8°C (47°F).

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

September Precipitation in Rosemont

In Rosemont in September, the precipitation amount is 3 mm (0.1 in) during a total of 0 days.

September Precipitation Trends in Rosemont

The chart displays monthly precipitation patterns in Rosemont, 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 Rosemont, September typically receives around 3 mm (0.1 inches) of precipitation spread over approximately 0 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 Rosemont

In Rosemont in September humidity is 44%. With an average temperature of 23°C (73°F), this humidity feels like a pleasant embrace, making it comfortable for travelers to explore and enjoy outdoor activities without feeling too sticky or overheated.

September Average Humidity in Rosemont

This chart illustrates the average monthly humidity levels in Rosemont, 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 Rosemont is approximately 44%, 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 Rosemont

In Rosemont in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Rosemont.

Maximum UV Index Levels in Rosemont for September

The chart shows the monthly maximum UV Index (UVI) for Rosemont 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 Rosemont typically reaches 9, which falls under the very high exposure category.

Data source: Rosemont 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 Rosemont Compares to Other Months

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

This table compares monthly weather conditions in Rosemont, 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 (49°F)	128 mm (5.0 inches)	84%	moderate
February Weather	11°C (52°F)	118 mm (4.7 inches)	84%	moderate
March Weather	13°C (55°F)	119 mm (4.7 inches)	83%	high
April Weather	16°C (62°F)	54 mm (2.1 inches)	81%	very high
May Weather	20°C (68°F)	25 mm (1.0 inches)	74%	very high
June Weather	24°C (75°F)	5 mm (0.2 inches)	64%	extreme
July Weather	25°C (77°F)	0 mm (0.0 inches)	44%	extreme
August Weather	25°C (77°F)	0 mm (0.0 inches)	36%	very high
September Weather	23°C (73°F)	3 mm (0.1 inches)	44%	very high
October Weather	18°C (65°F)	41 mm (1.6 inches)	65%	high
November Weather	13°C (55°F)	66 mm (2.6 inches)	84%	moderate
December Weather	9°C (48°F)	116 mm (4.6 inches)	83%	moderate