August weather forecastSeattle, WA
August
Weather in August
August maintains the summer heat, with temperatures nearly mirroring July's highs. Rain becomes even more scarce, and the city revels in clear, sun-drenched days. As the warmest sea temperatures take hold, August asserts itself as an excellent time for swim enthusiasts to take a dip in the calm waters. Its quintessential summer weather coincides with an array of outdoor events and festivals, contributing to the joyful atmosphere all around the city. Summer is at its peak and the city is alive with energy and excitement.Temperature
During the warmest month, August, temperatures average a high of 76.3°F (24.6°C) and a low of 54°F (12.2°C).Humidity
The average relative humidity in August in Seattle is 70%.Rainfall
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.Snowfall
In Seattle, snow does not fall in April through October and December.Ocean temperature
With an average ocean temperature of 53.6°F (12°C), August is the month with the warmest seawater.Note: Diving into 53.6°F (12°C) is practical below 50°F (10°C), given you're wearing protective swim gear; without it, expect a quick onset of cold shock and a struggle to breathe. Merely touching waters at 55.4°F (13°C) feels ice-cold.
Daylight
In August, the average length of the day is 14h and 12min.On the first day of August, sunrise is at 5:48 am and sunset at 8:43 pm. On the last day of the month, sunrise is at 6:27 am and sunset at 7:50 pm PDT.
Sunshine
August has the most sunshine of the year, with an average of 10.7h of sunshine.UV index
In Seattle, the average daily maximum UV index in August is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for ordinary individuals.Note: A maximum daily UV index of 4 during August morphs into the following directions:
Act with care - The need to guard against sun damage is communicated. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Opt for tightly woven and loose clothing to enhance protection from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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).
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).
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).
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%).
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").
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).
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").
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).
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).
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 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- 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).
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).
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).
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).
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).
