Mercer Island (WA) Sunshine Hours by Month

Sunshine plays a big role in understanding the climate of a city. This page shows the total number of hours of direct sunlight per month and the average hours per day in Mercer Island, Washington State, United States of America. These averages rely on historical data collected over 30 years, from 1990 to 2020.

Monthly hours of sunshine

Seasonal sunshine in Mercer Island varies. It peaks at 312 hours in July and drops to 54 hours in December. The total annual amount of sun is 2171 hours.

Daily hours of sunshine

This means the city can be enjoyed more throughout the sunniest month of July under a blue sky, with approximately 10.4 hours of sunshine daily. In contrast, the city experiences much darker days in December, with only 1.8 hours of sunlight per day.

Average percent of sunshine

On average the sun shines 65% of the time during the day in July, the highest percentage of any month. December has the lowest percentage at 20%.

Mercer Island vs Major Cities: Sunshine Compared

Mercer Island enjoys an average of 2171 hours of sunshine annually. Let’s compare this with some popular tourist destinations:

The city of Rome, Italy, experiences 2470 hours of sunshine annually, adding to its charm as a year-round tourist destination.

Manchester, UK, experiences just around 1420 hours of sunshine annually.

Meanwhile, Buenos Aires, Argentina, enjoys a humid subtropical climate with 2520 hours of sunshine annually.

Melbourne, Australia, has 2380 hours of sunshine annually, with its famous “four seasons in a day” weather pattern.

Related Climate Data for Mercer Island

November, Mercer Island’s wettest month, receives 25 mm (1 in) of rainfall and has a maximum daytime temperature of 11°C (52°F). During the driest month July you can expect a temperature of 25°C (77°F).

For more detailed insights into the city’s temperatures, check out our Temperature page. To explore more about precipitation patterns, visit our Mercer Island Precipitation page.