September Weather in Algonquin, United States

Last updated: June 24, 2025

In September, the average temperature in Algonquin, United States hovers around 23°C (74°F). Visitors can expect a minimum temperature of 12°C (53°F) and a maximum of 32°C (90°F). With 99 mm (3.9 in) of precipitation spread over 9 days, the air feels quite humid, boasting an average humidity level of 75%.

September Temperature in Algonquin

In September in Algonquin, the average temperature is 23°C (74°F). The maximum can reach 32°C (90°F), while the minimum can drop to as low as 12°C (53°F). This pleasant climate makes it an ideal time for travelers to explore and enjoy the diverse activities that Algonquin has to offer.

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

The chart illustrates September temperature patterns in Algonquin, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Algonquin, September typically has an average temperature of 23°C (74°F), with highs reaching up to 32°C (90°F) and lows dropping to around 12°C (53°F).

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

September Precipitation in Algonquin

In Algonquin in September, the precipitation amount is 99 mm (3.9 in) during a span of 9 days.

September Precipitation Trends in Algonquin

The chart displays monthly precipitation patterns in Algonquin, 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 Algonquin, September typically receives around 99 mm (3.9 inches) of precipitation spread over approximately 9 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 Algonquin

In Algonquin in September, humidity is 75%. With an average temperature of 23°C (74°F), this humidity feels like a warm, heavy blanket wrapping around you, making it feel more sweltering than it actually is, which can be quite uncomfortable for traveling.

September Average Humidity in Algonquin

This chart illustrates the average monthly humidity levels in Algonquin, 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 Algonquin is approximately 75%, 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 Algonquin

In Algonquin 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 Algonquin.

Maximum UV Index Levels in Algonquin for September

The chart shows the monthly maximum UV Index (UVI) for Algonquin 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 Algonquin typically reaches 8, which falls under the very high exposure category.

Data source: Algonquin 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 Algonquin Compares to Other Months

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

This table compares monthly weather conditions in Algonquin, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	4°C (39°F)	68 mm (2.7 inches)	84%	moderate
February Weather	5°C (42°F)	101 mm (4.0 inches)	83%	moderate
March Weather	8°C (47°F)	88 mm (3.5 inches)	83%	high
April Weather	14°C (57°F)	86 mm (3.4 inches)	81%	very high
May Weather	19°C (66°F)	115 mm (4.5 inches)	78%	very high
June Weather	24°C (75°F)	90 mm (3.5 inches)	79%	very high
July Weather	27°C (81°F)	136 mm (5.4 inches)	74%	very high
August Weather	26°C (79°F)	148 mm (5.8 inches)	72%	very high
September Weather	23°C (74°F)	99 mm (3.9 inches)	75%	very high
October Weather	18°C (65°F)	118 mm (4.7 inches)	81%	high
November Weather	10°C (51°F)	86 mm (3.4 inches)	85%	moderate
December Weather	6°C (44°F)	100 mm (3.9 inches)	84%	moderate