What’s the climate like in Mercer Island?
The current climate in Mercer Island features temperatures ranging from a high of 26°C to a low of 9°C throughout the year. The average yearly temperature is around 17°C. At night, temperatures in the colder months average around 3°C and in the warmer months around 16°C.
The highest temperature recorded in Mercer Island in recent years was 41°C in June 2021. The lowest daytime temperature recorded was -5°C in December 2021.
On average, Mercer Island gets 1547 mm of precipitation each year. Of this, about 27 cm is snowfall. For comparison, New York gets 1142 mm of precipitation each year.
Best time to visit Mercer Island?
The best time to visit Mercer Island for sunny weather is May through September. During this period, you'll have nice temperatures and not too much rain, making it a great time to visit Mercer Island. In the other months of the year, there's too much rain or the temperature isn't ideal for a visit if you want sunny and pleasant weather.
Climate Table of Mercer Island
The climate table of Mercer Island shows the average temperatures, rainfall, snow, and UV index per month. The table provides an overview of the average day and night temperatures in degrees Celsius, the total amount of rainfall in millimeters, the total snowfall in centimeters, and the UV index for each month. Rainfall is always measured as water, even if it's snow or hail.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temp. max (°C) | 10 | 10 | 13 | 16 | 20 | 22 | 26 | 26 | 22 | 17 | 11 | 9 |
| Temp. min (°C) | 5 | 4 | 5 | 8 | 11 | 13 | 16 | 16 | 13 | 10 | 6 | 4 |
| Precipitation |  |
|
|
|
|
|
|
|
|
|
|
|
| Precipitation (mm) | 196 | 176 | 148 | 138 | 55 | 50 | 9,3 | 15 | 60 | 175 | 267 | 257 |
| Snow (cm) | 1,4 | 9,5 | 0 | 1,2 | 0 | 0 | 0 | 0 | 0 | 0 | 4,8 | 10 |
| UV Index | 1 | 2 | 3 | 3 | 6 | 7 | 7 | 7 | 3 | 2 | 2 | 1 |
Click on the month name to see more weather details, like daily averages, temperatures, and precipitation for the past years in that month.
- Average yearly temperature: 17°C
- Highest temperature: 26°C in July and August
- Lowest temperature: 9°C in December
- Precipitation*: 1547 mm per year, averaging 129 mm per month
- Snowfall: 27 cm per year
- Driest months: 9,3 mm in July, 15 mm in August and 50 mm in June
- Wettest months: 267 mm in November, 257 mm in December and 196 mm in January
*Precipitation is measured as a combination of rain, snow, and hail
Plan your next vacation
Don’t miss the best vacation deals for Mercer Island and see what our partners have for you.
Table of Contents
Average Temperature per Month in Mercer Island
This graph shows the average maximum temperatures per month in Mercer Island, Washington. The temperatures are shown in degrees Celsius and the average is calculated based on the recorded temperatures per month from past years.
Average Precipitation per Month in Mercer Island
This graph shows how much rainfall Mercer Island, Washington, gets on average per month. Rainfall is always measured as water, even if it's snow or hail. This makes it easy to compare how much has fallen, regardless of the form of precipitation. The amount of rainfall is measured in millimeters, and the average is calculated based on the recorded rainfall per month from past years.
Average Snowfall per Month in Mercer Island
This graph shows how much snow Mercer Island, Washington, gets on average per month. The amount of snowfall is measured in centimeters and the average is calculated based on the recorded snowfall per month from past years.
Average UV Index per Month in Mercer Island
This graph shows the average UV index per month in Mercer Island, Washington. The UV index indicates the intensity of ultraviolet radiation and ranges from 0 to a maximum of 11.
Yearly Temperature in Mercer Island
This graph shows the average yearly temperature in Mercer Island, Washington. The yearly temperature, expressed in degrees Celsius, is the average of all twelve monthly temperatures summed up for that year.
Total Yearly Precipitation in Mercer Island
This chart shows the total yearly precipitation in Mercer Island, Washington, over the past few years. The total yearly precipitation, measured in millimeters, is the sum of all the rain that fell in the twelve months of that year.
Total Yearly Snowfall in Mercer Island
This chart shows the total yearly snowfall in Mercer Island, Washington, over the past few years. The total yearly snowfall, measured in centimeters, is the sum of all the snow that fell in the twelve months of that year.
Weather experiences in Mercer Island
Have you been to Mercer Island?
Share your weather experiences in Mercer Island.
Average Weather in Mercer Island by Month
Click on a month below to see detailed weather info for Mercer Island. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
