September Weather in Harrisburg, United States

Last updated: June 24, 2025

In Harrisburg, United States, the average temperature in September hovers around 23°C (75°F). Daily highs can soar to a sizzling 35°C (95°F), while chilly nights may drop to a brisk 8°C (46°F). Expect a total precipitation of about 133 mm (5.2 in) over 9 days, accompanied by an average humidity level of 75%, creating a warm yet refreshing atmosphere perfect for exploration!

September Temperature in Harrisburg

In September in Harrisburg, the average temperature is 23°C (75°F). The maximum can reach 35°C (95°F) and the minimum can be as low as 8°C (46°F). This makes Harrisburg an ideal destination for travelers looking to enjoy a pleasant climate with a range of temperatures suitable for various activities.

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

The chart illustrates September temperature patterns in Harrisburg, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Harrisburg, September typically has an average temperature of 23°C (75°F), with highs reaching up to 35°C (95°F) and lows dropping to around 8°C (46°F).

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

September Precipitation in Harrisburg

In Harrisburg in September, the precipitation amount is 133 mm (5.2 in) spread over a duration of 9 days.

September Precipitation Trends in Harrisburg

The chart displays monthly precipitation patterns in Harrisburg, 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 Harrisburg, September typically receives around 133 mm (5.2 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 Harrisburg

In Harrisburg in September humidity is 75%. With an average temperature of 23°C (75°F), this humidity feels like walking through a warm, damp blanket, which can make outdoor activities a bit sluggish but also lovely for exploring shaded areas and enjoying refreshing drinks.

September Average Humidity in Harrisburg

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

In Harrisburg 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 Harrisburg.

Maximum UV Index Levels in Harrisburg for September

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

Data source: Harrisburg 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 Harrisburg Compares to Other Months

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

This table compares monthly weather conditions in Harrisburg, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	6°C (44°F)	92 mm (3.6 inches)	86%	moderate
February Weather	9°C (49°F)	116 mm (4.6 inches)	85%	high
March Weather	12°C (54°F)	83 mm (3.3 inches)	84%	very high
April Weather	17°C (62°F)	103 mm (4.0 inches)	82%	very high
May Weather	22°C (71°F)	113 mm (4.5 inches)	83%	very high
June Weather	25°C (77°F)	82 mm (3.2 inches)	82%	extreme
July Weather	27°C (81°F)	114 mm (4.5 inches)	80%	very high
August Weather	26°C (79°F)	105 mm (4.1 inches)	74%	very high
September Weather	23°C (75°F)	133 mm (5.2 inches)	75%	very high
October Weather	18°C (65°F)	92 mm (3.6 inches)	79%	very high
November Weather	10°C (51°F)	90 mm (3.5 inches)	87%	moderate
December Weather	8°C (47°F)	120 mm (4.7 inches)	87%	moderate