nomadseason

August Weather in Grand Coulee, United States

Last updated: June 24, 2025

In Grand Coulee, United States, the average temperature in August hovers around 23°C (74°F). While temperatures can dip to a brisk 8°C (46°F), they can also soar to an impressive 39°C (102°F). Visitors should prepare for a modest precipitation of 8 mm (0.3 in) spread over 2 days, accompanied by an average humidity level of 62%.

August Temperature in Grand Coulee

In August in Grand Coulee, the average temperature is 23°C (74°F), with maximums reaching up to 39°C (102°F) and minimums dropping as low as 8°C (46°F). Travelers should be prepared for a wide range of temperatures to fully enjoy their stay.

August Weather in Grand Coulee: Daily Temperature Highs, Lows, and Averages

The chart illustrates August temperature patterns in Grand Coulee, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Grand Coulee, August typically has an average temperature of 23°C (74°F), with highs reaching up to 39°C (102°F) and lows dropping to around 8°C (46°F).
JanFebMarAprMayJunJulAugSepOctNovDec282839485967757362473729
Data source: Temperature data for Grand Coulee generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

August Precipitation in Grand Coulee

In Grand Coulee in August, the precipitation amount is 8 mm (0.3 in) over the course of 2 days.

August Precipitation Trends in Grand Coulee

The chart displays monthly precipitation patterns in Grand Coulee, 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 Grand Coulee, August typically receives around 8 mm (0.3 inches) of precipitation spread over approximately 2 days.
JanFebMarAprMayJunJulAugSepOctNovDec6747464037134824425157
Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

August Humidity in Grand Coulee

In Grand Coulee in August humidity is 62%. With an average temperature of 23°C (74°F), this humidity feels like a warm, slightly sticky embrace, making it essential for travelers to stay hydrated and wear breathable clothing while exploring.

August Average Humidity in Grand Coulee

This chart illustrates the average monthly humidity levels in Grand Coulee, 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 Grand Coulee is approximately 62%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%86%86%82%77%79%77%62%60%80%87%86%
Data source: Humidity data for August generated using information from the Copernicus Climate Change Service.

August UV Index in Grand Coulee

In Grand Coulee 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 Grand Coulee.

Maximum UV Index Levels in Grand Coulee for August

The chart shows the monthly maximum UV Index (UVI) for Grand Coulee 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 Grand Coulee typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec245689997532
Data source: Grand Coulee 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 Grand Coulee Compares to Other Months

Weather in Grand Coulee varies notably across the year, with each month offering distinct climate conditions. This page compares August’s weather to other months in Grand Coulee, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Grand Coulee, showing how August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (28°F)67 mm (2.6 inches)85%low
February Weather-2°C (28°F)47 mm (1.9 inches)86%moderate
March Weather4°C (39°F)46 mm (1.8 inches)86%moderate
April Weather9°C (48°F)39 mm (1.6 inches)82%high
May Weather15°C (59°F)37 mm (1.4 inches)77%very high
June Weather20°C (68°F)13 mm (0.5 inches)79%very high
July Weather24°C (75°F)4 mm (0.1 inches)77%very high
August Weather23°C (74°F)8 mm (0.3 inches)62%very high
September Weather17°C (62°F)24 mm (1.0 inches)60%high
October Weather8°C (48°F)42 mm (1.7 inches)80%moderate
November Weather3°C (37°F)51 mm (2.0 inches)87%moderate
December Weather-2°C (29°F)57 mm (2.2 inches)86%low

Compare Grand Coulee's Climate with Cities Worldwide