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September Weather in Hillsboro, United States

Last updated: June 24, 2025

In Hillsboro, United States, the average temperature in September is a pleasant 24°C (76°F). Expect a climate where the minimum dips to a cool 12°C (54°F), while the maximum can reach a sweltering 36°C (97°F). Rainfall totals around 102 mm (4.0 in) spread across 8 days, contributing to an average humidity of 64%. This makes for a vibrant yet varied weather experience!

September Temperature in Hillsboro

In September in Hillsboro, the average temperature is 24°C (76°F). The maximum can reach 36°C (97°F), and the minimum can be as low as 12°C (54°F). This makes it an ideal time for travelers to enjoy a comfortable climate while exploring the attractions.

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 24°C (76°F), with highs reaching up to 36°C (97°F) and lows dropping to around 12°C (54°F).
JanFebMarAprMayJunJulAugSepOctNovDec444956627278818076665148
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 102 mm (4.0 in) over the course of 8 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 102 mm (4.0 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec1141781751471051189910710210871144
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 64%. With an average temperature of 24°C (76°F), this humidity feels like a warm, sticky embrace, making travel slightly uncomfortable but still enjoyable, as you may find yourself yearning for a refreshing breeze or a quick dip in the water.

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 64%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%87%85%82%83%82%78%67%64%75%87%89%
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.
JanFebMarAprMayJunJulAugSepOctNovDec46810111111109754
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 Weather7°C (44°F)114 mm (4.5 inches)87%moderate
February Weather9°C (49°F)178 mm (7.0 inches)87%high
March Weather13°C (56°F)175 mm (6.9 inches)85%very high
April Weather17°C (62°F)147 mm (5.8 inches)82%very high
May Weather22°C (72°F)105 mm (4.1 inches)83%extreme
June Weather25°C (78°F)118 mm (4.7 inches)82%extreme
July Weather27°C (81°F)99 mm (3.9 inches)78%extreme
August Weather27°C (80°F)107 mm (4.2 inches)67%very high
September Weather24°C (76°F)102 mm (4.0 inches)64%very high
October Weather19°C (66°F)108 mm (4.2 inches)74%high
November Weather11°C (51°F)71 mm (2.8 inches)87%moderate
December Weather9°C (48°F)144 mm (5.7 inches)88%moderate

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