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September Weather in Harrisburg, United States

Last updated: June 24, 2025

In September, the average temperature in Harrisburg, United States hovers around 17°C (63°F). Expect minimum temperatures to dip as low as 4°C (39°F), while the mercury can rise to a sweltering 36°C (97°F) on warmer days. With an average precipitation of 71 mm (2.8 in) over 6 days, and humidity levels at 71%, prepare for a month of varied weather and rich experiences!

September Temperature in Harrisburg

In September in Harrisburg, the average temperature is 17°C (63°F). Maximum temperatures can reach 36°C (97°F), while minimums can drop as low as 4°C (39°F). Be prepared for a wide range of temperatures during your travels.

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 17°C (63°F), with highs reaching up to 36°C (97°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec414145505662686963534641
Data source: Temperature data for Harrisburg generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Harrisburg

In Harrisburg in September, the precipitation amount is 71 mm (2.8 in) over a span of 6 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 71 mm (2.8 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec1601921401256448367191143195
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Harrisburg

In Harrisburg in September, humidity is 71%. With an average temperature of 17°C (63°F), this humidity feels like a warm embrace, making outdoor activities enjoyable yet a bit sticky, so travelers should stay hydrated and take breaks in the shade.

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.
JanFebMarAprMayJunJulAugSepOctNovDec85%84%85%83%83%84%82%74%71%81%87%87%
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 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 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 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec246710101098532
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.
 TemperaturePrecipitationHumidityUV
January Weather5°C (42°F)160 mm (6.3 inches)85%low
February Weather5°C (41°F)192 mm (7.5 inches)84%moderate
March Weather7°C (45°F)140 mm (5.5 inches)85%high
April Weather10°C (50°F)125 mm (4.9 inches)83%high
May Weather13°C (56°F)64 mm (2.5 inches)83%very high
June Weather17°C (62°F)48 mm (1.9 inches)83%very high
July Weather20°C (68°F)2 mm (0.1 inches)82%very high
August Weather20°C (69°F)6 mm (0.2 inches)74%very high
September Weather17°C (63°F)71 mm (2.8 inches)71%very high
October Weather11°C (53°F)91 mm (3.6 inches)81%moderate
November Weather8°C (46°F)143 mm (5.6 inches)87%moderate
December Weather5°C (41°F)195 mm (7.7 inches)87%low

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