August Weather in Portland, United States

Last updated: June 24, 2025

In Portland, United States, the average temperature in August hovers around 23°C (74°F). Expect a comfortable range, with minimum temperatures dipping to 10°C (51°F) and highs soaring to 34°C (94°F). During this month, precipitation totals 102 mm (4.0 in) over approximately 11 days, contributing to an average humidity level of 79%.

August Temperature in Portland

In August in Portland, the average temperature is 23°C (74°F). Maximum temperatures can reach up to 34°C (94°F), while the minimum can drop as low as 10°C (51°F). This makes Portland an ideal destination for travelers seeking a mix of warm days and cooler nights.

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 (74°F), with highs reaching up to 34°C (94°F) and lows dropping to around 10°C (51°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 precipitation amount is 102 mm (4.0 in) over the course of 11 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 102 mm (4.0 inches) of precipitation spread over approximately 11 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 79%. With an average temperature of 23°C (74°F), this humidity feels like a warm, enveloping blanket that can make outdoor activities a bit less comfortable, urging travelers to seek shade and hydration throughout the day.

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 79%, 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	-2°C (29°F)	74 mm (2.9 inches)	85%	moderate
February Weather	0°C (32°F)	88 mm (3.4 inches)	85%	moderate
March Weather	5°C (42°F)	101 mm (4.0 inches)	86%	high
April Weather	10°C (51°F)	93 mm (3.7 inches)	87%	very high
May Weather	17°C (63°F)	127 mm (5.0 inches)	81%	very high
June Weather	22°C (73°F)	114 mm (4.5 inches)	82%	extreme
July Weather	24°C (76°F)	101 mm (4.0 inches)	81%	very high
August Weather	23°C (74°F)	102 mm (4.0 inches)	79%	very high
September Weather	20°C (69°F)	75 mm (2.9 inches)	78%	very high
October Weather	14°C (57°F)	97 mm (3.8 inches)	81%	high
November Weather	5°C (42°F)	82 mm (3.2 inches)	89%	moderate
December Weather	2°C (35°F)	67 mm (2.7 inches)	86%	low