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August Weather in Portland, United States

Last updated: June 24, 2025

In Portland, United States, the average temperature in August hovers around 22°C (71°F), with a minimum of 15°C (60°F) and a maximum of 27°C (81°F). Expect around 85 mm (3.3 in) of precipitation over 13 days, contributing to an average humidity of 72%. Prepare for a month that balances warmth and moisture!

August Temperature in Portland

In August in Portland, the average temperature is 22°C (71°F). The maximum can reach 27°C (81°F), while the minimum can dip as low as 15°C (60°F). It's a pleasant time for visiting, with comfortable temperatures for outdoor activities and sightseeing.

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 22°C (71°F), with highs reaching up to 27°C (81°F) and lows dropping to around 15°C (60°F).
JanFebMarAprMayJunJulAugSepOctNovDec292934415163717166564235
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 85 mm (3.3 in) spread over 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 85 mm (3.3 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec9898951121111021268588151125128
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 72%. With an average temperature of 22°C (71°F), this humidity feels like a warm embrace, making outdoor activities enjoyable but potentially sticky, urging travelers to stay hydrated and take breaks in the shade.

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 72%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec91%91%88%88%82%80%77%72%76%83%88%87%
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.
JanFebMarAprMayJunJulAugSepOctNovDec24689101098642
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 Weather-2°C (29°F)98 mm (3.9 inches)91%low
February Weather-1°C (30°F)98 mm (3.9 inches)91%moderate
March Weather1°C (34°F)95 mm (3.7 inches)88%high
April Weather5°C (41°F)112 mm (4.4 inches)88%very high
May Weather11°C (52°F)111 mm (4.4 inches)82%very high
June Weather17°C (63°F)102 mm (4.0 inches)79%very high
July Weather22°C (72°F)125 mm (4.9 inches)77%very high
August Weather22°C (71°F)85 mm (3.3 inches)72%very high
September Weather19°C (66°F)88 mm (3.5 inches)76%very high
October Weather13°C (56°F)151 mm (5.9 inches)83%high
November Weather6°C (43°F)125 mm (4.9 inches)88%moderate
December Weather2°C (36°F)128 mm (5.0 inches)87%low

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