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September Weather in Hillsboro, United States

Last updated: June 24, 2025

In September, the average temperature in Hillsboro, United States hovers around 22°C (71°F), making it a pleasant time to visit. However, be prepared for a temperature range that can dip to 6°C (43°F) or rise to a steamy 34°C (93°F). Rainfall is moderate, with an accumulation of about 65 mm (2.6 in) over approximately 6 days. Don't forget to anticipate the average humidity level of 79%, adding a touch of tropical feel to your adventures!

September Temperature in Hillsboro

In September in Hillsboro, the average temperature is 22°C (71°F). Maximum temperatures can reach 34°C (93°F), while minimums can drop as low as 6°C (43°F). This makes it a great time to explore Hillsboro with a diverse range of weather conditions to suit different activities.

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

The chart illustrates September temperature patterns in Hillsboro, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hillsboro, September typically has an average temperature of 22°C (71°F), with highs reaching up to 34°C (93°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec303345546676787571584237
Data source: Temperature data for Hillsboro 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 Hillsboro

In Hillsboro, in September, the precipitation amount is 65 mm (2.6 in) over a period of 6 days.

September Precipitation Trends in Hillsboro

The chart displays monthly precipitation patterns in Hillsboro, 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 Hillsboro, September typically receives around 65 mm (2.6 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec7678129140158113103116651097657
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Hillsboro

In Hillsboro in September humidity is 79%. With an average temperature of 22°C (71°F), this humidity feels like a warm, sticky embrace that can make any outdoor adventure quite challenging for traveling; it's advisable to stay hydrated and take breaks in the shade to fully enjoy the sights.

September Average Humidity in Hillsboro

This chart illustrates the average monthly humidity levels in Hillsboro, 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 Hillsboro is approximately 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%84%83%80%83%82%83%79%79%88%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Hillsboro

In Hillsboro 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 Hillsboro.

Maximum UV Index Levels in Hillsboro for September

The chart shows the monthly maximum UV Index (UVI) for Hillsboro 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 Hillsboro typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910111199643
Data source: Hillsboro 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 Hillsboro Compares to Other Months

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

This table compares monthly weather conditions in Hillsboro, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (31°F)76 mm (3.0 inches)84%moderate
February Weather1°C (34°F)78 mm (3.1 inches)82%moderate
March Weather7°C (45°F)129 mm (5.1 inches)84%high
April Weather12°C (54°F)140 mm (5.5 inches)83%very high
May Weather19°C (66°F)158 mm (6.2 inches)80%very high
June Weather24°C (76°F)113 mm (4.4 inches)83%extreme
July Weather26°C (78°F)103 mm (4.1 inches)82%extreme
August Weather24°C (75°F)116 mm (4.6 inches)82%very high
September Weather22°C (71°F)65 mm (2.6 inches)79%very high
October Weather14°C (58°F)109 mm (4.3 inches)79%high
November Weather6°C (43°F)76 mm (3.0 inches)88%moderate
December Weather3°C (37°F)57 mm (2.3 inches)87%moderate

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