September Weather in Harrisburg, United States

Last updated: June 24, 2025

In September, the average temperature in Harrisburg, United States is a pleasant 24°C (76°F). However, be prepared for some extremes, as temperatures can dip to a minimum of 9°C (49°F) and soar to a maximum of 35°C (96°F). Expect 86 mm (3.4 in) of precipitation spread over about 8 days, contributing to an average humidity of 71%.

September Temperature in Harrisburg

In September in Harrisburg, the average temperature is 24°C (76°F). The maximum can reach 35°C (96°F), while the minimum can be as low as 9°C (49°F). This makes Harrisburg a great destination for travelers seeking warm weather, but it's wise to pack layers for cooler evenings.

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 24°C (76°F), with highs reaching up to 35°C (96°F) and lows dropping to around 9°C (49°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 reaches 86 mm (3.4 in) over the course of 8 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 86 mm (3.4 inches) of precipitation spread over approximately 8 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 71%. With an average temperature of 24°C (76°F), this humidity feels like a warm, tropical embrace, making it essential to stay hydrated while exploring, as the air is thick and can leave you feeling sticky and slightly tired after even short excursions.

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 71%, 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	5°C (41°F)	100 mm (3.9 inches)	84%	moderate
February Weather	7°C (45°F)	172 mm (6.8 inches)	83%	high
March Weather	12°C (54°F)	166 mm (6.5 inches)	81%	very high
April Weather	16°C (61°F)	136 mm (5.4 inches)	81%	very high
May Weather	22°C (72°F)	146 mm (5.8 inches)	83%	extreme
June Weather	26°C (79°F)	114 mm (4.5 inches)	83%	extreme
July Weather	28°C (82°F)	112 mm (4.4 inches)	81%	extreme
August Weather	26°C (80°F)	108 mm (4.3 inches)	74%	very high
September Weather	24°C (76°F)	86 mm (3.4 inches)	71%	very high
October Weather	18°C (64°F)	129 mm (5.1 inches)	76%	high
November Weather	10°C (50°F)	78 mm (3.1 inches)	84%	moderate
December Weather	8°C (46°F)	134 mm (5.3 inches)	88%	moderate