Mercer Island, WA Weather Forecast
Local 7-day forecast
Mostly Sunny
Track current conditions, temperature changes, wind, and the full daily outlook for Mercer Island, WA in one place.
Mostly sunny, with a high near 76. West wind 2 to 6 mph.
Local Weather Overview
This forecast page for Mercer Island, WA is designed for quick trip planning, giving you a clean read on daytime highs, overnight lows, and changing conditions across the upcoming forecast window. Latest sync: Jul 17, 2026 12:10 AM PDT.
The active forecast window currently covers Jul 18 to Jul 23, 2026 for Mercer Island, WA.
Page Snapshot
- Page focus
- city weather
- Forecast window
- Jul 18 to Jul 23, 2026
- Latest sync
- Jul 17, 2026 12:10 AM PDT
- Forecast office
- SEW
- Source
- NOAA / NWS
Daily Outlook
This Week in Mercer Island
Tuesday looks like the warmest upcoming period in Mercer Island at 89 degrees F.
Saturday Night is the coolest period ahead with temperatures near 58 degrees F.
The strongest winds are forecast for Saturday Night at about 1 to 8 mph N.
The forecast from Jul 18 through Jul 23 stays mostly dry.
Forecast Details
- Last updated
- Jul 17, 2026 12:10 AM PDT
- Coverage
- 6 days
- Time zone
- America/Los_Angeles
- Forecast office
- SEW
- Radar station
- KATX
Weather data is provided by the National Weather Service and refreshed automatically for U.S. locations.
Open NOAA sourceExtended Forecast
Mostly clear, with a low around 58. North wind 1 to 8 mph.
Sunny, with a high near 81.
Mostly clear, with a low around 60.
Mostly sunny, with a high near 86.
Partly cloudy, with a low around 64.
Mostly sunny, with a high near 89.
Partly cloudy, with a low around 65.
Mostly sunny, with a high near 88.
Mostly clear, with a low around 64.
Sunny, with a high near 86.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Saturday
Jul 18
|
Mostly Sunny
|
76°F |
2 to 6 mph
W
|
|
Saturday Night
Jul 18
|
Mostly Clear
|
58°F |
1 to 8 mph
N
|
|
Sunday
Jul 19
|
Sunny
|
81°F |
1 to 7 mph
N
|
|
Sunday Night
Jul 19
|
Mostly Clear
|
60°F |
2 to 7 mph
N
|
|
Monday
Jul 20
|
Mostly Sunny
|
86°F |
2 to 7 mph
N
|
|
Monday Night
Jul 20
|
Partly Cloudy
|
64°F |
0 to 6 mph
N
|
|
Tuesday
Jul 21
|
Mostly Sunny
|
89°F |
0 to 5 mph
NNW
|
|
Tuesday Night
Jul 21
|
Partly Cloudy
|
65°F |
5 mph
WSW
|
|
Wednesday
Jul 22
|
Mostly Sunny
|
88°F |
2 to 6 mph
WSW
|
|
Wednesday Night
Jul 22
|
Mostly Clear
|
64°F |
2 to 6 mph
WNW
|
|
Thursday
Jul 23
|
Sunny
|
86°F |
2 to 6 mph
WSW
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around Mercer Island.
