August weather forecast
Seattle, WA

Beautiful dusk skyline over the giant skyscrapers of Seattle, Washington
Beautiful dusk skyline over the giant skyscrapers of Seattle, Washington

Weather in August

August, the last month of the summer in Seattle, is also a moderately hot month, with an average temperature varying between 76.3°F (24.6°C) and 54°F (12.2°C).

Temperature

With an average high-temperature of 76.3°F (24.6°C) and an average low-temperature of 54°F (12.2°C), August is the warmest month.

Humidity

In August, the average relative humidity in Seattle is 70%.

Rainfall

The months with the least rainfall in Seattle are July and August Rain falls for 2.8 days and accumulates 0.12" (3mm) of rain.

Snowfall

April through October and December are months without snowfall.

Ocean temperature

With an average ocean temperature of 53.6°F (12°C), August is the month with the warmest seawater.
Note: Swimming in 53.6°F (12°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

Daylight

In August, the average length of the day in Seattle is 14h and 12min.
On the first day of August, sunrise is at 5:47 am and sunset at 8:44 pm. On the last day of the month, sunrise is at 6:26 am and sunset at 7:52 pm PDT.

Sunshine

With an average of 10.7h of sunshine, August has the most sunshine of the year.

UV index

In Seattle, the average daily maximum UV index in August is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: The daily maximum UV index of 4 in August interpret into the following advice:
Take precautions - Protection against sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the warmest month in Seattle?

The warmest month in Seattle is August, with an average high-temperature of 76.3°F (24.6°C) and an average low-temperature of 54°F (12.2°C).

What is the temperature in August in Seattle?

In Seattle, Washington, in August, the average high-temperature is 76.3°F (24.6°C), and the average low-temperature is 54°F (12.2°C).

What is the average humidity in August in Seattle?

In August, the average relative humidity in Seattle is 70%.

What is the driest month in Seattle?

July and August are months with the least rain in Seattle when the rain falls for 2.8 days and typically aggregates up to 0.12" (3mm) of rain.

How many days does it rain in August in Seattle?

In Seattle, in August, during 2.8 rainfall days, 0.12" (3mm) of precipitation is typically accumulated.

When it does not snow in Seattle?

In Seattle, Washington, snow does not fall in April through October and December.

What month is the ocean warmest in Seattle?

The month with the warmest seawater is August, with an average ocean temperature of 53.6°F (12°C).

How cold is the water in August in Seattle?

In August, the average ocean temperature in Seattle is 53.6°F (12°C). Swimming in 53.6°F (12°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

How many hours of daylight does Seattle have in August?

The average day length in August in Seattle is 14h and 12min.

When are sunrise and sunset in August in Seattle?

On the first day of August, sunrise is at 5:47 am and sunset at 8:44 pm. On the last day of the month, sunrise is at 6:26 am and sunset at 7:52 pm PDT.

What month has the most sunshine in Seattle?

August has the most sunshine of the year in Seattle, with an average of 10.7h of sunshine.

How many hours of sunshine does Seattle have in August?

In August, the average sunshine duration in Seattle is 10.7h.

What is the UV index reading in August in Seattle?

In August, the average daily maximum UV index in Seattle, Washington, is 4. A UV Index reading of 3 to 5 represents a medium health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Seattle, WA

Average temperature in August - Seattle, WA
  • Average high temperature in August: 76.3°F

The warmest month (with the highest average high temperature) is August (76.3°F).
The month with the lowest average high temperature is December (43.7°F).

  • Average low temperature in August: 54°F

The month with the highest average low temperature is August (54°F).
The coldest month (with the lowest average low temperature) is December (35.1°F).

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Average pressure in August
Seattle, WA

Average pressure in August - Seattle, WA
  • Average pressure in August: 30.01"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).

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Average wind speed in August
Seattle, WA

Average wind speed in August - Seattle, WA
  • Average wind speed in August: 3.5mph

The windiest month (with the highest average wind speed) is March (5.3mph).
The calmest months (with the lowest average wind speed) are July and August (3.5mph).

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Average humidity in August
Seattle, WA

Average humidity in August - Seattle, WA
  • Average humidity in August: 70%

The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is July (69%).

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Average rainfall in August
Seattle, WA

Average rainfall in August - Seattle, WA
  • Average rainfall in August: 0.12"

The wettest month (with the highest rainfall) is December (0.87").
The driest months (with the least rainfall) are July and August (0.12").

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Average rainfall days in August
Seattle, WA

Average rainfall days in August - Seattle, WA
  • Average rainfall days in August: 2.8 days

The month with the highest number of rainy days is November (9.1 days).
The month with the least rainy days is August (2.8 days).

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Average snowfall in August
Seattle, WA

Average snowfall in August - Seattle, WA
  • Average snowfall in August: 0"

The month with the highest snowfall is February (0.71").
The months with the least snowfall are April, May, June, July, August, September, October and December (0").

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Average snowfall days in August
Seattle, WA

Average snowfall days in August - Seattle, WA
  • Average snowfall days in August: 0 days

The month with the highest number of snowfall days is February (1.9 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average sea temperature in August
Seattle, WA

Average sea temperature in August - Seattle, WA
  • Average sea temperature in August: 53.5°F

The best month for swimming (with the highest average sea temperature) is August (53.5°F).
The coldest month (with the lowest average sea temperature) is February (45.3°F).

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Average daylight in August /
Average sunshine in August
Seattle, WA

Average daylight in August / Average sunshine in August - Seattle, WA
  • Average daylight in August: 14h and 12min

The month with the longest days is June (Average daylight: 15h and 55min).
The month with the shortest days is December (Average daylight: 8h and 31min).

  • Average sunshine in August: 10h and 42min

The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 18min).

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Average sunshine days in August
Seattle, WA

Average sunshine days in August - Seattle, WA
  • Average sunshine days in August: 25.9 days

The month with the most sunshine days is August (25.9 days).
The month with the least sunshine days is November (16.8 days).

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Average UV index in August
Seattle, WA

Average UV index in August - Seattle, WA
  • Average UV index in August: 4

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in August
Seattle, WA

Average cloud cover in August - Seattle, WA
  • Average cloud cover in August: 25

The month with the most cloud cover is December (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 25).

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Average visibility in August
Seattle, WA

Average visibility in August - Seattle, WA
  • Average visibility in August: 6mi

The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March, November and December (5mi).

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