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WeatherLive › Washington › Mercer Island

Mercer Island, WA Weather (98040)

Today Hourly 10-Day Weekend Monthly Radar Air Quality Climate
Current WeatherMercer Island · 9:55 AM PDT
85° | 56°
64°F
Feels like 64°
Mostly cloudy
WindS 4 mph · Gusts 6 mph
Precip6% · –
Humidity78% · Dew point 57°
UV index6 High
Air Quality57 Moderate
Pressure30.06 inHg
Visibility6 mi
Sunrise / Sunset6:10 AM · 8:14 PM · 14h 4m

Weather map — Mercer Island

Full radar →
Now
64°
23%
4 mph
10:00
68°
18%
4 mph
11:00
71°
15%
5 mph
12:00
74°
12%
4 mph
13:00
78°
9%
4 mph
14:00
81°
1%
4 mph
15:00
84°
7%
2 mph
16:00
85°
9%
2 mph
17:00
85°
4%
2 mph
18:00
84°
2%
2 mph
19:00
81°
1%
4 mph
20:00
74°
4%
6 mph
21:00
70°
3%
5 mph
22:00
67°
3%
5 mph
23:00
65°
4%
4 mph
00:00
64°
17%
3 mph
01:00
63°
18%
3 mph
02:00
62°
15%
3 mph
03:00
61°
10%
3 mph
04:00
60°
9%
2 mph
05:00
59°
9%
2 mph
06:00
59°
10%
2 mph
07:00
60°
9%
1 mph
08:00
63°
6%
1 mph

Today · Wed 8/19

High 85°
6% / –

Sunny. Winds N at 6 mph.

Tonight · Wed 8/19

Low 59°
3% / –

Sunny. Winds N at 5 mph.

Tomorrow · Thu 8/20

86° | 59°
3% / –

Sunny. Winds N at 7 mph.

7-day trend

Mercer Island · temperature + precipitation

10-day forecast

Updated 9:55 AM

Details & indices

Wind
4 mph S
Gusts 6 mph
Humidity
78%
Dew point 57°
Pressure
30.06 inHg
Rising
UV index
6 — High
High today
Air Quality
Moderate
AQI 57 · US EPA
Allergy
Very high
Mugwort
Visibility
6 mi
Clear view
Allergy — Mercer Island

🌿 Conditions right now

View all →
Birch
None
Grass
High
Oak
None
Alder
None
Hazel
None
Mugwort
Very high
Ragweed
None

Sun & moon

Sunrise6:10 AM
Sunset8:14 PM
Length of day14h 4m
Moonrise2:36 PM
Moonset10:51 PM
Moon phase🌓 First Quarter · 46%
Next full moonAug 27 Sturgeon Moon
Latitude47.5707°N
Longitude-122.2221°E

Water temps nearby

View all →
No beaches within 50 miles
🌤️No rain expected in the next 90 minutes
Now+30+60+90 min
Minute-by-minute precip · HRRR nowcast

Daily planner

computed from today's forecast
Laundry day
Great
Line-drying weather
Grilling
Great
Fire up the grill
Running
Fair
Lace up outside
Patio
Great
Dinner outdoors
Nearby places in {{REGION}}
🌤️
Seattle
—
— 🌤️
Tri-Cities
—
— 🌤️
Spokane
—
— 🌤️
Tacoma
—
—
Vancouver
Mostly cloudy
64°
Data sources · Wednesday, August 19
Where the Mercer Island forecast comes from
This page blends NOAA/NWS model guidance with global ensembles for the 10-day outlook, air quality and alerts. Data refreshes every hour, current conditions every 15 minutes. Coordinates: 47.5707°N, -122.2221°.
NBM + global weather models
Updated: 9:55 AM
Weather in Mercer Island
Mercer Island's outlook: warmest day near 86° (Thursday), coldest night about 51° (Friday). Roughly 0.11 in of rain falls over the period, with Friday the most likely wet day (57%). No active NWS alerts at the moment — quiet on the hazards front. Right now Mercer Island is about 10° cooler than nearby Tri-Cities. Longer view: marine climate — mild, showery winters and dry, gentle summers.
Mercer Island, WA · Elev 335 ft · 47.57°N, 122.22°W · Washington · Forecast computed for these exact coordinates
Powered by NWS/NOAA guidance, multi-model forecasts and official environmental feeds · NOAA/NWS · EPA AirNow · MET Norway · global models
Updated: 9:55 AM