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September Weather in Hillsborough, United States

Last updated: June 24, 2025

In September, the average temperature in Hillsborough, United States is a mild 17°C (63°F), with a minimum dropping to 0°C (32°F) and a peak reaching up to 32°C (90°F). During this month, expect about 87 mm (3.4 in) of precipitation over 8 days, contributing to an average humidity of 71%.

September Temperature in Hillsborough

In September in Hillsborough, the average temperature is 17°C (63°F). The maximum can reach 32°C (90°F) and the minimum can be as low as 0°C (32°F). It's a great time to explore Hillsborough, so be prepared for both warm days and cool nights.

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

The chart illustrates September temperature patterns in Hillsborough, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hillsborough, September typically has an average temperature of 17°C (63°F), with highs reaching up to 32°C (90°F) and lows dropping to around 0°C (32°F).
JanFebMarAprMayJunJulAugSepOctNovDec242733455667727063513728
Data source: Temperature data for Hillsborough 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 Hillsborough

In Hillsborough in September, the precipitation amount is 87 mm (3.4 in), which occurs over a span of 8 days.

September Precipitation Trends in Hillsborough

The chart displays monthly precipitation patterns in Hillsborough, 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 Hillsborough, September typically receives around 87 mm (3.4 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec748881130868914010187135104120
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Hillsborough

In Hillsborough 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 Hillsborough

This chart illustrates the average monthly humidity levels in Hillsborough, 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 Hillsborough is approximately 71%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%82%80%72%72%67%66%71%79%84%81%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Hillsborough

In Hillsborough in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Hillsborough.

Maximum UV Index Levels in Hillsborough for September

The chart shows the monthly maximum UV Index (UVI) for Hillsborough 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 Hillsborough typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3468910997632
Data source: Hillsborough 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 Hillsborough Compares to Other Months

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

This table compares monthly weather conditions in Hillsborough, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (24°F)74 mm (2.9 inches)86%moderate
February Weather-3°C (27°F)88 mm (3.5 inches)84%moderate
March Weather0°C (33°F)81 mm (3.2 inches)82%high
April Weather7°C (45°F)130 mm (5.1 inches)80%very high
May Weather14°C (57°F)86 mm (3.4 inches)72%very high
June Weather19°C (67°F)89 mm (3.5 inches)72%very high
July Weather22°C (72°F)140 mm (5.5 inches)67%very high
August Weather21°C (70°F)101 mm (4.0 inches)66%very high
September Weather17°C (63°F)87 mm (3.4 inches)71%high
October Weather11°C (52°F)135 mm (5.3 inches)78%high
November Weather3°C (37°F)104 mm (4.1 inches)84%moderate
December Weather-2°C (28°F)120 mm (4.7 inches)81%low

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