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September Weather in Oregon, United States

Last updated: June 24, 2025

In September, the average temperature in Oregon, United States is a pleasant 22°C (71°F). Visitors can expect a minimum drop to 6°C (43°F) and a potential high of 35°C (96°F). Be prepared for some rain, as the region typically receives 83 mm (3.2 in) of precipitation over 9 days. With an average humidity of around 71%, the climate is both warm and somewhat humid, making it a perfect time to explore!

September Temperature in Oregon

In September in Oregon, the average temperature is 22°C (71°F). Maximums can reach 35°C (96°F) and minimums can be as low as 6°C (43°F). This variability in temperatures makes it essential for travelers to pack both lightweight clothing for the warm days and warmer layers for the cooler nights.

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

The chart illustrates September temperature patterns in Oregon, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Oregon, September typically has an average temperature of 22°C (71°F), with highs reaching up to 35°C (96°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec283045536577797671554235
Data source: Temperature data for Oregon 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 Oregon

In Oregon, in September, the precipitation amount is 83 mm (3.2 in) spread over a period of 9 days.

September Precipitation Trends in Oregon

The chart displays monthly precipitation patterns in Oregon, 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 Oregon, September typically receives around 83 mm (3.2 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec41319282168133120110831234032
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Oregon

In Oregon in September, humidity is 71%. With an average temperature of 22°C (71°F), this humidity feels like a warm embrace, making outdoor activities enjoyable yet requiring plenty of hydration to stay comfortable while exploring.

September Average Humidity in Oregon

This chart illustrates the average monthly humidity levels in Oregon, 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 Oregon is approximately 71%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%78%70%73%82%82%81%78%71%71%81%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Oregon

In Oregon 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 Oregon.

Maximum UV Index Levels in Oregon for September

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

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

This table compares monthly weather conditions in Oregon, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (29°F)41 mm (1.6 inches)76%moderate
February Weather-1°C (30°F)31 mm (1.2 inches)77%moderate
March Weather7°C (45°F)92 mm (3.6 inches)70%high
April Weather12°C (53°F)82 mm (3.2 inches)73%very high
May Weather18°C (65°F)168 mm (6.6 inches)82%very high
June Weather25°C (77°F)132 mm (5.2 inches)82%extreme
July Weather26°C (79°F)119 mm (4.7 inches)81%extreme
August Weather24°C (76°F)110 mm (4.3 inches)78%very high
September Weather22°C (71°F)83 mm (3.2 inches)71%very high
October Weather13°C (56°F)123 mm (4.8 inches)71%high
November Weather6°C (43°F)40 mm (1.6 inches)81%moderate
December Weather2°C (36°F)32 mm (1.3 inches)84%moderate

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