August weather forecastMercer Island, WA
August
Weather in August
The last month of the summer, August, is also a moderately hot month in Mercer Island, Washington, with an average temperature ranging between max 76.6°F (24.8°C) and min 53.4°F (11.9°C).Temperature
Mercer Island, Washington, experiences its highest average temperatures in August, reaching a peak of 76.6°F (24.8°C) and a minimum of 53.4°F (11.9°C).Humidity
In August, the average relative humidity is 70%.Rainfall
In Mercer Island, Washington, in August, it is raining for 4.1 days, with typically 0.31" (8mm) of accumulated precipitation. Throughout the year, there are 119.1 rainfall days, and 11.97" (304mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall.Daylight
In Mercer Island, Washington, the average length of the day in August is 14h and 12min.On the first day of the month, sunrise is at 5:47 am and sunset at 8:42 pm. On the last day of August, 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 Mercer Island, the average daily maximum UV index in August is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the ordinary person.Note: A daily maximum UV index of 4 in August translates into the following instructions:
Take precautions - Protection against skin and eye damage is obliged. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in August
Mercer Island, WA
- Average high temperature in August: 76.6°F
The warmest month (with the highest average high temperature) is August (76.6°F).
The month with the lowest average high temperature is December (42.8°F).
- Average low temperature in August: 53.4°F
The month with the highest average low temperature is August (53.4°F).
The coldest month (with the lowest average low temperature) is February (34.5°F).
Average pressure in August
Mercer Island, WA
- Average pressure in August: 30"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).
Average wind speed in August
Mercer Island, WA
- Average wind speed in August: 3.4mph
The windiest month (with the highest average wind speed) is March (5.1mph).
The calmest month (with the lowest average wind speed) is August (3.4mph).
Average humidity in August
Mercer Island, 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
Mercer Island, WA
- Average rainfall in August: 0.31"
The wettest month (with the highest rainfall) is December (2.01").
The driest month (with the least rainfall) is July (0.24").
Average rainfall days in August
Mercer Island, WA
- Average rainfall days in August: 4.1 days
The month with the highest number of rainy days is March (13.7 days).
The month with the least rainy days is August (4.1 days).
Average snowfall in August
Mercer Island, WA
- Average snowfall in August: 0"
The month with the highest snowfall is February (1.77").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in August
Mercer Island, WA
- Average snowfall days in August: 0 days
The month with the highest number of snowfall days is February (3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in August /
Average sunshine in August
Mercer Island, 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 12min).
Average sunshine days in August
Mercer Island, WA
- Average sunshine days in August: 24.9 days
The month with the most sunshine days is August (24.9 days).
The month with the least sunshine days is February (13.8 days).
Average UV index in August
Mercer Island, 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
Mercer Island, 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
Mercer Island, WA
- Average visibility in August: 6mi
The months with the highest visibility are May, June, July, August and September (6mi).
The months with the lowest visibility are January, February, March, April, October, November and December (5mi).
