September Weather in Astoria, United States

Last updated: June 24, 2025

In September, the average temperature in Astoria, United States is a pleasant 21°C (71°F). Temperatures can vary widely, with a minimum of 6°C (43°F) and a maximum reaching up to 35°C (95°F). Expect an average precipitation of 71 mm (2.8 in) spread over approximately 7 days. With an average humidity of 78%, it's advisable to be prepared for a mix of warm and humid conditions.

September Temperature in Astoria

In September in Astoria, the average temperature is 21°C (71°F). Maximum temperatures can reach 35°C (95°F), while minimums can drop as low as 6°C (43°F). Overall, it's a great time to explore Astoria with warm days and cooler nights, perfect for outdoor adventures.

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

The chart illustrates September temperature patterns in Astoria, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Astoria, September typically has an average temperature of 21°C (71°F), with highs reaching up to 35°C (95°F) and lows dropping to around 6°C (43°F).

Data source: Temperature data for Astoria generated using information from the Copernicus Climate Change Service.

September Precipitation in Astoria

In Astoria in September, the precipitation amount is 71 mm (2.8 in) over a span of 7 days.

September Precipitation Trends in Astoria

The chart displays monthly precipitation patterns in Astoria, 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 Astoria, September typically receives around 71 mm (2.8 inches) of precipitation spread over approximately 7 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Astoria

In Astoria in September humidity is 78%. With an average temperature of 21°C (71°F), this humidity feels like a warm blanket wrapped around you, making travel a bit more challenging as it can lead to a sticky, heavy sensation, dampening the enjoyment of outdoor activities.

September Average Humidity in Astoria

This chart illustrates the average monthly humidity levels in Astoria, 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 Astoria is approximately 78%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Astoria

In Astoria 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 Astoria.

Maximum UV Index Levels in Astoria for September

The chart shows the monthly maximum UV Index (UVI) for Astoria 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 Astoria typically reaches 8, which falls under the very high exposure category.

Data source: Astoria 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 Astoria Compares to Other Months

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

This table compares monthly weather conditions in Astoria, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-2°C (28°F)	62 mm (2.4 inches)	81%	moderate
February Weather	-1°C (31°F)	66 mm (2.6 inches)	81%	moderate
March Weather	6°C (43°F)	127 mm (5.0 inches)	81%	high
April Weather	11°C (52°F)	110 mm (4.3 inches)	82%	very high
May Weather	18°C (65°F)	164 mm (6.5 inches)	78%	very high
June Weather	24°C (75°F)	135 mm (5.3 inches)	81%	extreme
July Weather	25°C (78°F)	103 mm (4.0 inches)	79%	very high
August Weather	24°C (75°F)	89 mm (3.5 inches)	77%	very high
September Weather	21°C (71°F)	71 mm (2.8 inches)	78%	very high
October Weather	14°C (57°F)	108 mm (4.3 inches)	78%	high
November Weather	5°C (41°F)	59 mm (2.3 inches)	87%	moderate
December Weather	2°C (35°F)	51 mm (2.0 inches)	84%	low