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August Weather in Portland, United States

Last updated: June 24, 2025

In August, the average temperature in Portland, United States is a pleasant 23°C (74°F). Expect a range of temperatures with a minimum of 11°C (53°F) and a maximum of 34°C (94°F). Be prepared for some rain, as the region experiences 96 mm (3.8 in) of precipitation spread over 11 days. With an average humidity of 65%, it’s a great time to enjoy the outdoors while staying hydrated!

August Temperature in Portland

In August in Portland, the average temperature is 23°C (74°F). Maximum can reach 34°C (94°F) and minimum can be as low as 11°C (53°F). This climate makes Portland an ideal destination for travelers seeking warm and pleasant weather.

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 11°C (53°F).
JanFebMarAprMayJunJulAugSepOctNovDec323439495969757467574436
Data source: Temperature data for Portland 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.

August Precipitation in Portland

In Portland in August, the precipitation amount is 96 mm (3.8 in) spread over 11 days, resulting in a significant accumulation of rainfall.

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 96 mm (3.8 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec67909012611194156969913090127
Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.
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August Humidity in Portland

In Portland in August, humidity is 65%. With an average temperature of 23°C (74°F), this humidity feels like a warm, sticky embrace, making outdoor activities somewhat challenging but still enjoyable with the right planning.

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 65%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%81%78%70%69%62%65%68%74%82%80%
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.
JanFebMarAprMayJunJulAugSepOctNovDec35681010998642
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.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)67 mm (2.6 inches)84%moderate
February Weather1°C (34°F)89 mm (3.5 inches)82%moderate
March Weather4°C (40°F)90 mm (3.6 inches)81%high
April Weather10°C (49°F)126 mm (5.0 inches)78%very high
May Weather15°C (60°F)111 mm (4.4 inches)69%very high
June Weather20°C (69°F)94 mm (3.7 inches)69%very high
July Weather24°C (75°F)156 mm (6.1 inches)62%very high
August Weather23°C (74°F)96 mm (3.8 inches)65%very high
September Weather20°C (67°F)99 mm (3.9 inches)68%very high
October Weather14°C (58°F)130 mm (5.1 inches)74%high
November Weather7°C (44°F)90 mm (3.6 inches)82%moderate
December Weather2°C (36°F)127 mm (5.0 inches)80%low

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