September Weather in De Kalb, United States

Last updated: June 24, 2025

In September, the average temperature in De Kalb, United States hovers around 25°C (78°F), creating a pleasantly warm atmosphere. Expect temperatures to fluctuate between a cool 11°C (52°F) and a scorching 38°C (100°F). With a precipitation amount of 97 mm (3.8 in) spread over 9 days, it’s wise to prepare for occasional showers. Outdoor enthusiasts should also note the average humidity level is a comfortable 74%, making it a great time to explore this beautiful destination!

September Temperature in De Kalb

In September in De Kalb, the average temperature is 25°C (78°F). Maximums can reach 38°C (100°F) and minimums can be as low as 11°C (52°F). This makes it an ideal time for travelers to enjoy a mix of warm days and cooler evenings.

September Weather in De Kalb: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in De Kalb, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In De Kalb, September typically has an average temperature of 25°C (78°F), with highs reaching up to 38°C (100°F) and lows dropping to around 11°C (52°F).

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

September Precipitation in De Kalb

In De Kalb in September, the total precipitation amount reaches 97 mm (3.8 in) over the course of 9 days.

September Precipitation Trends in De Kalb

The chart displays monthly precipitation patterns in De Kalb, 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 De Kalb, September typically receives around 97 mm (3.8 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 De Kalb

In De Kalb in September humidity is 74%. With an average temperature of 25°C (78°F), this humidity feels like you're enveloped in a warm, thick blanket, making outdoor activities feel more strenuous and necessitating frequent breaks and hydration for comfortable travel.

September Average Humidity in De Kalb

This chart illustrates the average monthly humidity levels in De Kalb, 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 De Kalb is approximately 74%, 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 De Kalb

In De Kalb 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 De Kalb.

Maximum UV Index Levels in De Kalb for September

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

Data source: De Kalb 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 De Kalb Compares to Other Months

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

This table compares monthly weather conditions in De Kalb, 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 (48°F)	105 mm (4.1 inches)	85%	moderate
February Weather	12°C (53°F)	160 mm (6.3 inches)	84%	high
March Weather	15°C (60°F)	120 mm (4.7 inches)	82%	very high
April Weather	18°C (65°F)	148 mm (5.8 inches)	82%	very high
May Weather	23°C (74°F)	120 mm (4.7 inches)	82%	extreme
June Weather	26°C (79°F)	167 mm (6.6 inches)	79%	extreme
July Weather	27°C (81°F)	109 mm (4.3 inches)	82%	extreme
August Weather	27°C (81°F)	129 mm (5.1 inches)	77%	extreme
September Weather	25°C (78°F)	97 mm (3.8 inches)	74%	very high
October Weather	20°C (69°F)	109 mm (4.3 inches)	73%	very high
November Weather	12°C (55°F)	66 mm (2.6 inches)	85%	high
December Weather	11°C (51°F)	120 mm (4.7 inches)	88%	moderate