September Weather in Jefferson, United States

Last updated: June 24, 2025

In September, the average temperature in Jefferson, United States is a comfortable 20°C (68°F). However, you can expect temperatures to range from a chilly 4°C (40°F) to a warm 34°C (94°F). Prepare for some moisture too, as the region receives about 101 mm (4.0 in) of precipitation over 9 days. With an average humidity of 75%, be ready for a pleasantly humid climate!

September Temperature in Jefferson

In September in Jefferson, the average temperature is 20°C (68°F). Maximum temperatures can reach 34°C (94°F), while minimums can drop to as low as 4°C (40°F). This diverse temperature range makes Jefferson an ideal destination for travelers who enjoy a mix of warm and cool weather experiences.

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

The chart illustrates September temperature patterns in Jefferson, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Jefferson, September typically has an average temperature of 20°C (68°F), with highs reaching up to 34°C (94°F) and lows dropping to around 4°C (40°F).

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

September Precipitation in Jefferson

In Jefferson in September, the total precipitation amount is 101 mm (4.0 in), occurring over a span of 9 days.

September Precipitation Trends in Jefferson

The chart displays monthly precipitation patterns in Jefferson, 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 Jefferson, September typically receives around 101 mm (4.0 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 Jefferson

In Jefferson 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 Jefferson

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

In Jefferson 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 Jefferson.

Maximum UV Index Levels in Jefferson for September

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

Data source: Jefferson 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 Jefferson Compares to Other Months

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

This table compares monthly weather conditions in Jefferson, 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)	28 mm (1.1 inches)	80%	moderate
February Weather	-5°C (23°F)	29 mm (1.2 inches)	84%	moderate
March Weather	3°C (38°F)	81 mm (3.2 inches)	75%	moderate
April Weather	9°C (48°F)	80 mm (3.2 inches)	79%	very high
May Weather	16°C (61°F)	140 mm (5.5 inches)	74%	very high
June Weather	23°C (74°F)	102 mm (4.0 inches)	81%	extreme
July Weather	25°C (77°F)	66 mm (2.6 inches)	82%	very high
August Weather	23°C (73°F)	109 mm (4.3 inches)	80%	very high
September Weather	20°C (68°F)	101 mm (4.0 inches)	75%	very high
October Weather	10°C (51°F)	77 mm (3.0 inches)	77%	moderate
November Weather	3°C (38°F)	27 mm (1.0 inches)	85%	moderate
December Weather	-2°C (29°F)	41 mm (1.6 inches)	83%	low