Live Weather & Forecast
Weather in Mercer Island
Washington, United States · Real-time conditions & 3-day outlook
13°C
Feels like 13°C
56°F / Feels 56°F
Overcast
Mercer Island, Washington
🌞 Daytime
Updated: 2026-04-12 17:30
Humidity
72%
Wind
6.8 km/h NW
Wind Gust
8.5 km/h
Pressure
1008 mb
Visibility
16 km
UV Index
0.8
(Low)
Precipitation
0 mm
Cloud Cover
100%
Dew Point
9.4°C
Wind Degree
304°
Air Quality Index
US EPA: Good
UK DEFRA: Low (1)
CO
292.9 μg/m³
NO₂
15.7 μg/m³
O₃
52 μg/m³
SO₂
2.6 μg/m³
PM 2.5
11 μg/m³
PM 10
11.6 μg/m³
Weather Alerts 1
Met
· Severe · Future
Winter Storm Watch issued April 12 at 1:40PM PDT until April 16 at 5:00AM PDT by NWS Seattle WA
A strong weather system will bring snow, possibly heavy at times, to the Western Washington Cascades late Tuesday afternoon through late Wednesday night. * WHAT...Heavy snow possible. Total snow accumulations between 10 and 20 inches possible. Winds could gust as high as 35 mph. * WHERE...Cascades of Snohomish and Northern King Counties, Cascades of Whatcom and Skagit Counties, Cascades of Pierc...
Monitor the latest forecasts for updates on this situation.
Today's Hourly Forecast
24-hour breakdown for Mercer Island, Washington
12 AM
8°
Clear
1 AM
8°
Clear
2 AM
7°
Clear
3 AM
7°
Clear
4 AM
7°
Clear
5 AM
6°
Clear
6 AM
6°
Clear
7 AM
7°
Sunny
8 AM
9°
Sunny
9 AM
10°
Sunny
10 AM
11°
Sunny
11 AM
11°
Overcast
12 PM
12°
Overcast
1 PM
12°
Overcast
2 PM
13°
Overcast
3 PM
14°
Partly Cloudy
4 PM
13°
Cloudy
5 PM
13°
Overcast
6 PM
13°
Patchy rain nearby
7 PM
12°
Patchy rain nearby
8 PM
12°
Patchy rain nearby
9 PM
12°
Patchy rain nearby
10 PM
11°
Patchy rain nearby
11 PM
10°
Overcast
3-Day Forecast
Daily overview for Mercer Island, Washington
Today
Patchy rain nearby
14°
/
6°
🌧️ 88% chance of rain
💧 Avg. humidity: 85%
💨 Max wind: 9.4 km/h
🌧️ Total precip: 0.13 mm
☀️ UV Index: 1
🌅 Sunrise: 06:25 AM
🌇 Sunset: 07:55 PM
🌙 Waning Crescent
🌑 Moon: 33% lit
Mon, Apr 13
Patchy rain nearby
11°
/
7°
🌧️ 86% chance of rain
💧 Avg. humidity: 81%
💨 Max wind: 12.2 km/h
🌧️ Total precip: 0.12 mm
☀️ UV Index: 0.2
🌅 Sunrise: 06:23 AM
🌇 Sunset: 07:56 PM
🌙 Waning Crescent
🌑 Moon: 23% lit
Tue, Apr 14
Moderate rain
8°
/
6°
🌧️ 83% chance of rain
💧 Avg. humidity: 87%
💨 Max wind: 28.8 km/h
🌧️ Total precip: 16.24 mm
☀️ UV Index: 0.2
🌅 Sunrise: 06:21 AM
🌇 Sunset: 07:57 PM
🌙 Waning Crescent
🌑 Moon: 15% lit
Best Time to Visit Mercer Island
Plan your trip to Mercer Island, United States around the most favorable weather conditions.
Peak Season
June – September
Warm, dry summers — ideal for outdoor activities.
Shoulder Season
April – May, October
Fewer crowds, moderate prices, mild weather.
Off Season
November – March
Cooler temperatures; some regions may experience rain or snow.
Frequently Asked Questions
What is the current weather in Mercer Island?
Current conditions in Mercer Island: Overcast, temperature 13°C, humidity 72%.
What is the best time to visit Mercer Island?
The best time to visit Mercer Island is typically June – September. Warm, dry summers — ideal for outdoor activities.
What is the climate like in Mercer Island?
Mercer Island is located at approximately 47.6° latitude. It has a temperate climate with warm summers and cold winters.
Does it rain a lot in Mercer Island?
The wettest period in Mercer Island is typically during November – March. Cooler temperatures; some regions may experience rain or snow.
What should I pack for a trip to Mercer Island?
For visits to Mercer Island during June – September: light clothing and sun protection. For November – March: layers and a waterproof jacket are recommended.
What country is Mercer Island in?
Mercer Island is located in United States, in the state of Washington.
What are the public holidays in Mercer Island in 2026?
View the 2026 public holidays for Mercer Island on our Holidays page.
What are the GPS coordinates used for the weather forecast in Mercer Island?
The weather forecast for Mercer Island uses coordinates 47.5766, -122.2276.