Mercer Island (WA) Weather and Climate: A Comprehensive Guide
Mercer Island experiences great temperature shifts.
The city's weather can transition from warm days
to cold weather.
It is also known for its large amounts of rain/snowfall.
Let's now guide you through the climate details for a complete overview.
Average maximum day and minimum night temperature
The climate in Mercer Island is known for significant temperature differences throughout the year, making the weather dynamic. Typically, average maximum daytime temperatures range from a comfortable 25°C in August to a chilly 8°C in the coolest month, December.
Nights are cooler, with lows often dropping to around 2°C during the colder months. Check out our detailed temperature page for more information.Temperature ranges by month
Precipitation and rainy days
Mercer Island has a notably wet climate with abundant precipitation, recording 1045 mm of rain/snowfall per year. The climate in Mercer Island shows significant variation throughout the year. Expect heavy rainfall in November, with an average of 168 mm of precipitation over 21 rainy days. In contrast, July offers drier and sunnier days, with around 15 mm of rainfall over 4 rainy days. For more details, please visit our Mercer Island Precipitation page.The mean monthly precipitation over the year, including rain, hail and snow
The average number of days each month with precipitation
Sunshine over the year
For those who appreciate different seasons, Mercer Island serves as an ideal destination. Expect longer, more sun-filled days in July with an average of 10.4 hours of sunshine daily, and embrace the darker days in December, offering only 1.8 hours of daily sunlight. Visit our detailed sunshine hours page for more information.Monthly hours of sunshine
Daily hours of sunshine
Daily percentage of sunshine
Average humidity
The relative humidity is high throughout the year in Mercer Island.
The city experiences its highest humidity in December, reaching 80%. In July, the humidity drops to its lowest level at 65%. Explore our detailed page on humidity levels for further details.
Relative humidity over the year
Average wind speed
The average wind speed over the year ranges from 4 m/s to 5 m/s. It is lower in February, April, May, June, July, August, September, October, November and December and higher in January and March.
The mean monthly wind speed over the year (meters per second)
overcast and heavy rain broken clouds and rain broken clouds and rainForecast for Mercer Island (WA)
4 m/s
7 m/s
4 m/s
The best time of year to visit Mercer Island in the United States of America
During the months of June, July, August and September you are most likely to experience good weather with pleasant average temperatures that fall between 20°C and 26°C.Other facts from our historical weather data:
Most rainfall (rainy season) is seen in November and December.
August has an average maximum temperature of 25°C and is the warmest month of the year.
The coldest month is December with an average maximum temperature of 8°C.
November tops the wettest month list with 168 mm of rainfall.
July is the driest month with 15 mm of precipitation.
July is the sunniest month with an average of 312 hours of sunshine.
No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.
