August Weather in Portland, United States

Last updated: June 24, 2025

In August, the average temperature in Portland, United States is a comfortable 23°C (73°F). You can expect a minimum temperature of 12°C (53°F) and heat peaks reaching up to 34°C (93°F). Rainfall averages around 125 mm (4.9 in) spread over 13 days, with an average humidity of 62%, making it a month of warm days and occasional showers.

August Temperature in Portland

In August in Portland, the average temperature is 23°C (73°F). Maximums can reach 34°C (93°F) and minimums can be as low as 12°C (53°F). This pleasant climate makes Portland an ideal destination for outdoor activities and sightseeing during this time.

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

The chart illustrates August 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, August typically has an average temperature of 23°C (73°F), with highs reaching up to 34°C (93°F) and lows dropping to around 12°C (53°F).

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

August Precipitation in Portland

In Portland in August, the total precipitation amount is 125 mm (4.9 in), occurring over a span of 13 days.

August Precipitation Trends in Portland

The chart displays monthly precipitation patterns in Portland, with values for each month alongside August’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how August’s conditions compare to those of other months. In Portland, August typically receives around 125 mm (4.9 inches) of precipitation spread over approximately 13 days.

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

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Millimeters (mm) Inches (in)

August Humidity in Portland

In Portland in August humidity is 62%. With an average temperature of 23°C (73°F), this humidity feels like a warm, tropical embrace, making it perfect for travelers who enjoy exploring vibrant streets and outdoor attractions, though it can lead to a bit of stickiness that calls for frequent breaks in shaded spots or refreshing drinks.

August Average Humidity in Portland

This chart illustrates the average monthly humidity levels in Portland, with August’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In August, average humidity in Portland is approximately 62%, offering insight into how humid the weather typically is during this month.

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

August UV Index in Portland

In Portland in August, 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 Portland.

Maximum UV Index Levels in Portland for August

The chart shows the monthly maximum UV Index (UVI) for Portland in August, 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 August, the maximum UV index in Portland typically reaches 9, which falls under the very high exposure category.

Data source: Portland August 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 August 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 August’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 August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-1°C (31°F)	71 mm (2.8 inches)	87%	moderate
February Weather	1°C (34°F)	102 mm (4.0 inches)	85%	moderate
March Weather	4°C (39°F)	94 mm (3.7 inches)	85%	high
April Weather	10°C (50°F)	110 mm (4.3 inches)	83%	very high
May Weather	16°C (61°F)	135 mm (5.3 inches)	75%	very high
June Weather	21°C (69°F)	92 mm (3.6 inches)	73%	very high
July Weather	24°C (75°F)	124 mm (4.9 inches)	65%	very high
August Weather	23°C (73°F)	125 mm (4.9 inches)	62%	very high
September Weather	19°C (67°F)	107 mm (4.2 inches)	66%	very high
October Weather	14°C (57°F)	141 mm (5.5 inches)	79%	high
November Weather	6°C (42°F)	90 mm (3.5 inches)	87%	moderate
December Weather	2°C (35°F)	106 mm (4.2 inches)	85%	low