ClimateForecastNovemberDecember >>

Mercer Island (WA) Climate by Month

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 day and night temperature

The climate in Mercer Island is known for significant temperature differences throughout the year, making the weather dynamic. Typically, daytime temperatures range from a comfortable 25°C in August to a chilly 8°C in the coolest month, December. Nights are cooler, with temperatures generally dropping to 2°C, particularly during the colder months.

The mean minimum and maximum temperatures throughout the year

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.

The mean monthly precipitation over the year, including rain, hail and snow

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.

Monthly hours of sunshine

Data from: Seattle, the United States of America (15 KM, 9 Miles).

Daily hours of sunshine

Data from: Seattle, the United States of America (15 KM, 9 Miles).

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:
  • Which months have the greatest rainfall in Mercer Island?
    Most rainfall (rainy season) is seen in November and December.
  • Which is the warmest month in Mercer Island?
    August has an average maximum temperature of 25°C and is the warmest month of the year.
  • Which is the coldest month in Mercer Island?
    The coldest month is December with an average maximum temperature of 8°C.
  • Which is the wettest month in Mercer Island?
    November tops the wettest month list with 168 mm of rainfall.
  • Which is the driest month in Mercer Island?
    July is the driest month with 15 mm of precipitation.
  • Which is the sunniest month in Mercer Island?
    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.

    Forecast for Mercer Island (WA)

    Sat   Nov 23
    12°C | 6°C
    SW 14 km/h
    0.5 mm
    broken clouds and  chance of slight rain

    broken clouds and chance of slight rain

    Sun   Nov 24
    9°C | 5°C
    NE 7 km/h
    15 mm
    overcast and heavy rain

    overcast and heavy rain

    Mon   Nov 25
    10°C | 5°C
    W 7 km/h
    6.3 mm
    overcast and heavy rain

    overcast and heavy rain