September Weather in Vermillion, United States

Last updated: June 24, 2025

In September, the average temperature in Vermillion, United States reaches a pleasant 20°C (68°F). Expect a minimum of 5°C (41°F) and a comfortable maximum of 34°C (93°F). During this time, prepare for some rainfall, as 85 mm (3.3 in) of precipitation is expected over 9 days, contributing to an average humidity of 75%.

September Temperature in Vermillion

In September in Vermillion, the average temperature is 20°C (68°F). Maximums can reach 34°C (93°F) and minimums can be as low as 5°C (41°F). Travelers should be prepared for warm days and cool nights, making layering essentials for this time of year.

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

The chart illustrates September temperature patterns in Vermillion, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Vermillion, September typically has an average temperature of 20°C (68°F), with highs reaching up to 34°C (93°F) and lows dropping to around 5°C (41°F).

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

September Precipitation in Vermillion

In Vermillion in September, the precipitation amount is 85 mm (3.3 in) over the course of 9 days.

September Precipitation Trends in Vermillion

The chart displays monthly precipitation patterns in Vermillion, 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 Vermillion, September typically receives around 85 mm (3.3 inches) of precipitation spread over approximately 9 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Vermillion

In Vermillion in September, humidity is 75%. With an average temperature of 20°C (68°F), this humidity feels like a warm, muggy embrace that can leave travelers feeling sticky and exhausted.

September Average Humidity in Vermillion

This chart illustrates the average monthly humidity levels in Vermillion, 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 Vermillion 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 Vermillion

In Vermillion 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 Vermillion.

Maximum UV Index Levels in Vermillion for September

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

Data source: Vermillion 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 Vermillion Compares to Other Months

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

This table compares monthly weather conditions in Vermillion, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-5°C (23°F)	25 mm (1.0 inches)	80%	moderate
February Weather	-5°C (22°F)	26 mm (1.0 inches)	84%	moderate
March Weather	3°C (38°F)	79 mm (3.1 inches)	75%	high
April Weather	8°C (47°F)	85 mm (3.3 inches)	79%	very high
May Weather	16°C (60°F)	148 mm (5.8 inches)	74%	very high
June Weather	23°C (74°F)	94 mm (3.7 inches)	81%	extreme
July Weather	25°C (77°F)	82 mm (3.2 inches)	82%	very high
August Weather	23°C (73°F)	93 mm (3.7 inches)	80%	very high
September Weather	20°C (68°F)	85 mm (3.3 inches)	75%	very high
October Weather	10°C (50°F)	76 mm (3.0 inches)	77%	moderate
November Weather	3°C (37°F)	23 mm (0.9 inches)	85%	moderate
December Weather	-2°C (28°F)	42 mm (1.6 inches)	83%	low