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September Weather in Corvallis, United States

Last updated: June 24, 2025

In Corvallis, United States, the average temperature in September hovers around 17°C (64°F). However, be prepared for a temperature range that can dip to a brisk 4°C (39°F) or soar up to a sweltering 36°C (97°F). Expect about 61 mm (2.4 in) of precipitation spread over 7 days, accompanied by an average humidity of 71%, ensuring a refreshingly moist atmosphere throughout the month.

September Temperature in Corvallis

In September, in Corvallis, the average temperature is 17°C (64°F). The maximum can reach 36°C (97°F), while the minimum can drop as low as 4°C (39°F). This range makes Corvallis an ideal destination for those who enjoy varied weather and outdoor activities.

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

The chart illustrates September temperature patterns in Corvallis, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Corvallis, September typically has an average temperature of 17°C (64°F), with highs reaching up to 36°C (97°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec414145505663686963534641
Data source: Temperature data for Corvallis 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 Corvallis

In Corvallis in September, the precipitation amount is 61 mm (2.4 in) over the course of 7 days.

September Precipitation Trends in Corvallis

The chart displays monthly precipitation patterns in Corvallis, 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 Corvallis, September typically receives around 61 mm (2.4 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec1551791331176042356184139189
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Corvallis

In Corvallis in September humidity is 71%. With an average temperature of 17°C (64°F), this humidity feels like a warm, enveloping embrace that can make travel feel a bit sticky, yet still pleasant as you explore the sights with a gentle sheen of perspiration.

September Average Humidity in Corvallis

This chart illustrates the average monthly humidity levels in Corvallis, 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 Corvallis 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 Corvallis

In Corvallis 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 Corvallis.

Maximum UV Index Levels in Corvallis for September

The chart shows the monthly maximum UV Index (UVI) for Corvallis 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 Corvallis typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec246710101098532
Data source: Corvallis 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 Corvallis Compares to Other Months

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

This table compares monthly weather conditions in Corvallis, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather5°C (42°F)155 mm (6.1 inches)85%low
February Weather5°C (41°F)179 mm (7.0 inches)84%moderate
March Weather7°C (45°F)133 mm (5.2 inches)85%high
April Weather10°C (50°F)117 mm (4.6 inches)83%high
May Weather13°C (57°F)60 mm (2.3 inches)83%very high
June Weather17°C (63°F)42 mm (1.7 inches)83%very high
July Weather20°C (69°F)3 mm (0.1 inches)82%very high
August Weather21°C (69°F)5 mm (0.2 inches)74%very high
September Weather17°C (64°F)61 mm (2.4 inches)71%very high
October Weather12°C (53°F)84 mm (3.3 inches)81%moderate
November Weather8°C (46°F)139 mm (5.5 inches)87%moderate
December Weather5°C (41°F)189 mm (7.4 inches)87%low

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