September Weather in Portland, Australia

Last updated: August 22, 2025

In September, the average temperature in Portland, Australia hovers around 10°C (50°F), offering a mild yet varied climate. Expect lows dipping to -4°C (26°F) and highs reaching up to 27°C (82°F). Precipitation totals about 35 mm (1.4 in) spread over 5 days, while humidity levels remain comfortably at 69%. Perfect weather for exploring the unique offerings of the region!

September Temperature in Portland

In September in Portland, the average temperature is 10°C (50°F). Maximums can reach 27°C (82°F), while minimums can fall as low as -4°C (26°F). This temperature range means you should pack for both warm days and chilly nights during your travels.

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

The chart illustrates September temperature patterns in Portland, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Portland, September typically has an average temperature of 10°C (50°F), with highs reaching up to 27°C (82°F) and lows dropping to around -4°C (26°F).

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

September Precipitation in Portland

In Portland in September, the precipitation amount is 35 mm (1.4 in) over a span of 5 days.

September Precipitation Trends in Portland

The chart displays monthly precipitation patterns in Portland, 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 Portland, September typically receives around 35 mm (1.4 inches) of precipitation spread over approximately 5 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Portland

In Portland in September, humidity is 69%. With an average temperature of 10°C (50°F), this humidity feels like a cool mist that clings to your skin, making outdoor activities invigorating yet slightly damp, so travelers should dress in layers to adjust to the refreshing air.

September Average Humidity in Portland

This chart illustrates the average monthly humidity levels in Portland, 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 Portland is approximately 69%, 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 Portland

In Portland 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 Portland.

Maximum UV Index Levels in Portland for September

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

Data source: Portland 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 Portland Compares to Other Months

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

This table compares monthly weather conditions in Portland, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	21°C (70°F)	44 mm (1.7 inches)	55%	extreme
February Weather	19°C (66°F)	72 mm (2.8 inches)	60%	extreme
March Weather	17°C (63°F)	113 mm (4.4 inches)	68%	extreme
April Weather	13°C (56°F)	23 mm (0.9 inches)	74%	very high
May Weather	9°C (49°F)	26 mm (1.0 inches)	78%	high
June Weather	7°C (44°F)	28 mm (1.1 inches)	78%	moderate
July Weather	6°C (43°F)	33 mm (1.3 inches)	79%	moderate
August Weather	6°C (44°F)	46 mm (1.8 inches)	74%	high
September Weather	10°C (50°F)	35 mm (1.4 inches)	69%	very high
October Weather	14°C (57°F)	57 mm (2.3 inches)	57%	extreme
November Weather	16°C (61°F)	88 mm (3.5 inches)	53%	extreme
December Weather	19°C (66°F)	76 mm (3.0 inches)	62%	extreme