Mercer Island, WA Live Doppler Radar
Live radar for Mercer Island, King County: every NWS radar combined, rain, snow and ice colors, flash-flood risk, storm tracks and official warnings.
What weather hits Mercer Island?
Since 1996, the National Weather Service has logged lightning damage or injuries on 22 days in the Eastside forecast zone and King County — the most common reported hazard around Mercer Island, mostly in July and August. Next come flooding (7 days) and debris flows (4 days).
| Hazard | Days reported | Most recent | Worst on record |
|---|---|---|---|
| Lightning casualties & damage | 22 | Apr 2015 | Aug 3, 1999 · $650,000 damage |
| Flooding | 7 | Jan 2021 | Jan 7, 2009 · $14 million damage |
| Debris flows | 4 | Mar 2017 | Mar 2, 2014 · $200,000 damage |
| Damaging thunderstorm winds | 3 | May 2013 | May 13, 2013 · $25,000 damage |
| Flash flooding | 1 | Dec 2006 | Dec 14, 2006 · 1 death · $750,000 damage |
Source: NOAA NCEI Storm Events Database, 1996–2026 (the latest year is partial). A "day" is a date with at least one report in the Eastside forecast zone and King County; damage is as reported, not adjusted for inflation.
How much snow does Mercer Island get?
A normal year brings about 3.8 inches of snow to Mercer Island, based on NOAA's 1991–2020 climate normals for the Seattle Sand Pt Wsfo weather station 8.6 miles away. The snowiest month is usually December (1.7 in).
| Oct | Nov | Dec | Jan | Feb | Mar | Apr | May |
|---|---|---|---|---|---|---|---|
| 0.0 | 0.2 | 1.7 | 0.9 | 1.0 | 0.0 | 0.0 | 0.0 |
Normal snowfall in inches. TALON Pro compares this season's snow at your location with these normals as winter goes on.
Which radars cover Mercer Island?
The closest NEXRAD Doppler radar is KATX (Seattle/Tacoma, WA), about 45 miles north-northwest. Radar beams climb as they travel, so the height of the lowest scan over town decides how low in a storm the radar can see.
| Radar | Distance | Lowest beam over Mercer Island | View |
|---|---|---|---|
| KATX Seattle/Tacoma, WA | 45 mi north-northwest | 3,100 ft | Good — most storms and steady rain or snow show clearly |
| KLGX Langley Hill, WA | 93 mi west-southwest | 8,600 ft | Fair — the beam can pass over shallow snow and low-level rotation |
| KRTX Portland, OR | 132 mi south-southwest | 14,900 ft | Limited — the beam overshoots the lowest part of storms |
Beam height is the center of the 0.5° scan above the radar, with standard refraction. Mountains near a radar can block it further.
Tornado & hail history near Mercer Island
Since 1950, NOAA has recorded 9 tornadoes within 25 miles of Mercer Island, 2 of them EF2/F2 or stronger. Most came in December and June. The strongest was an F3 on December 12, 1969, which passed about 5 miles west-southwest of town. The most recent was an EF2 on December 18, 2018, which touched down about 18 miles west of town.
Hail: 2 reports of 1-inch or larger hail within 25 miles since 1955; the largest was 1.50-inch hail on June 8, 1972.
Source: NOAA Storm Prediction Center — tornadoes 1950–2025, hail 1955–2025. Distances are to each tornado's track; ratings before February 2007 use the original Fujita scale.
On TALON you get Mercer Island's live radar loop, rain/snow/ice colors, flash-flood risk, storm tracks with arrival times and NWS warnings free; close-up radar and rotation detection are part of TALON Pro.
Mercer Island radar FAQ
Where is the nearest weather radar to Mercer Island, WA?
KATX (Seattle/Tacoma, WA), about 45 miles north-northwest. KLGX (Langley Hill, WA) is 93 miles away and also covers the area.
Can radar see a tornado near Mercer Island?
Radar can't see the tornado itself, but it shows the rotating storm and, once debris is lofted, a debris signature. Over Mercer Island the lowest scan from KATX is about 3,100 ft up — good — most storms and steady rain or snow show clearly.
Is TALON's radar for Mercer Island free?
Yes — the US radar loop, rain/snow/ice colors, flash-flood risk, storm tracks and NWS warnings are free in any browser. Close-up radar, rotation detection and longer forecasts are part of TALON Pro.
Should I rely on radar for my safety?
No app replaces official warnings. When the National Weather Service issues a warning for Mercer Island, follow it right away — see watch vs. warning.
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