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August Weather in Portland, United States

Last updated: June 24, 2025

In Portland, United States during August, the average temperature reaches a warm 29°C (85°F), with highs soaring up to 35°C (96°F) and a comfortable low of 22°C (73°F). Expect precipitation of about 81 mm (3.2 in) over 11 days, contributing to an average humidity level of 78%. Enjoy the tropical vibes and prepare for some refreshing rain!

August Temperature in Portland

In August in Portland, the average temperature is 29°C (85°F). The maximum can reach 35°C (96°F) and the minimum can be as low as 22°C (73°F). This mild and warm climate makes Portland an ideal destination for travelers looking to enjoy 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 29°C (85°F), with highs reaching up to 35°C (96°F) and lows dropping to around 22°C (73°F).
JanFebMarAprMayJunJulAugSepOctNovDec586068737983848482756661
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 81 mm (3.2 in) over a span 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 81 mm (3.2 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec3931524413813610181141775247
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 78%. With an average temperature of 29°C (85°F), this humidity feels like a warm, thick blanket wrapping around you, making travel somewhat challenging as you adjust to the muggy conditions. The air feels heavy, and the heat can be intense, prompting frequent breaks to find shade and staying hydrated to keep fatigue at bay.

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 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec78%82%79%82%81%77%78%78%79%77%78%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 12, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, underscoring the importance of sun protection. 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 12, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec589111112121211975
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 Weather14°C (58°F)39 mm (1.5 inches)78%moderate
February Weather16°C (60°F)31 mm (1.2 inches)82%very high
March Weather20°C (68°F)52 mm (2.1 inches)79%very high
April Weather23°C (73°F)44 mm (1.7 inches)82%extreme
May Weather26°C (79°F)138 mm (5.4 inches)81%extreme
June Weather28°C (83°F)136 mm (5.4 inches)77%extreme
July Weather29°C (84°F)101 mm (4.0 inches)78%extreme
August Weather29°C (85°F)81 mm (3.2 inches)78%extreme
September Weather28°C (82°F)141 mm (5.6 inches)79%extreme
October Weather24°C (75°F)77 mm (3.0 inches)77%very high
November Weather19°C (66°F)51 mm (2.0 inches)78%high
December Weather16°C (61°F)47 mm (1.9 inches)80%moderate

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