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Northern lights Seattle tonight

Seattle sits at 54° magnetic latitude, so the threshold is Kp 4-5. The real obstacle is cloud cover - Seattle's marine climate delivers persistent overcast during aurora season. Hurricane Ridge in Olympic National Park at 1,640 meters often sits above the cloud layer. Driving east over the Cascades to Leavenworth, 2.5 hours away, roughly doubles your odds of clear sky. Best season: September to April.

Aurora visibility - Seattle

Unlikely tonight

Kp 1 is well below the Kp 4–5 threshold needed for aurora to be visible from Seattle.

Current Kp

of 9

Threshold for Seattle: Kp 4–5 Magnetic latitude: ~54°N Updated: 15 May, 17:56 UTC

↓ Bz — nT Solar wind — km/s Density — p/cm³ ☁ —%

Conditions right now: — Kp + Bz + solar wind + cloud + moon

7-day outlook for Seattle

Today

15 May

Quiet

Tomorrow

16 May

Quiet

Sun

17 May

Quiet

Mon

18 May

Quiet

Tue

19 May

Quiet

Wed

20 May

Quiet

Thu

21 May

Quiet

Based on CME arrival predictions from NASA DONKI. Arrival times ±6 hours.

What Kp is needed here?

Seattle sits at a magnetic latitude of approximately 54°N. The Kp index - a global measure of geomagnetic activity on a scale from 0 (quiet) to 9 (extreme storm), updated every 3 hours - needs to reach Kp 4–5 before the auroral oval expands far enough south to be visible from here.

At Kp 4–5, visibility is possible from Seattle but skies need to be clear and dark. Cloud cover and light pollution remain the main obstacles even when Kp is high enough.

Best dark sky sites near Seattle

Light pollution is the biggest obstacle after cloud cover. These sites give you the best dark northern horizon within reach.

Hurricane Ridge, Olympic National Park

1.5 hours from downtown Seattle including the ferry crossing from Edmonds to Kingston or Kingston-Edmonds ferry. The summit at 1,640 meters typically sits above the marine cloud layer that covers the Puget Sound lowlands. Olympic National Park holds International Dark Sky Park status, and the north-facing alpine terrain above the tree line gives open sky in all directions. The Hurricane Ridge Road is open year-round on weekends and daily in summer.

Deception Pass State Park

1 hour north of Seattle on the boundary between Whidbey and Fidalgo Islands. The north-facing coastline on Cranberry Lake and Bowman Bay faces open water toward the San Juan Islands with minimal light pollution. The dramatic bridge spanning the pass makes a distinctive foreground. Light pollution from Anacortes is visible to the east but does not affect the northern horizon.

Leavenworth area (east of the Cascades)

2.5 hours from Seattle via US-2 through Stevens Pass. The Cascade rain shadow drops cloud cover rates dramatically - Leavenworth averages around 300 clear nights per year versus Seattle's 160. Bortle 3-4 conditions in the Wenatchee National Forest north of town. The north-facing terrain above the Wenatchee River valley gives clear northern sightlines, and the mountain backdrop makes for strong aurora compositions when active.

Best time to see the northern lights in Seattle

Seattle's aurora season runs from late September through to March, when nights are long enough for truly dark skies. The equinox months, September and March, bring a natural boost in geomagnetic activity, making them statistically the best of the season. Summer months bring too much twilight for aurora to be visible at this latitude.

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Activity peaks around the September and March equinoxes, when Earth's magnetic field geometry is most favourable for coupling with the solar wind. Events during these two windows tend to produce the strongest displays of the year for observers at Seattle's latitude.

April through August brings persistent astronomical twilight that washes out aurora completely. Even strong events (Kp 6+) remain invisible during this period because the sky never gets dark enough.

Other USA aurora forecasts

← USA overview

Washington

Unlikely

Okanogan Highlands and North Cascades

~54°N mag. lat. Kp 5-6

Oregon

Unlikely

Alvord Desert Bortle 1-2, Crater Lake

~54°N mag. lat. Kp 5-6

Bozeman

Unlikely

Gallatin Valley, Yellowstone gateway, Montana

~54°N mag. lat. Kp 4

Northern Lights USA

USA-wide aurora forecast hub.

Northern Lights Washington State

Washington State aurora forecast, from Seattle to the Cascades.

Northern Lights Oregon

Oregon aurora forecast and dark sky locations.

Northern Lights Bozeman Tonight

Bozeman - Montana dark sky with more clear nights per year than Seattle.

What Is the Kp Index?

What Kp 4-5 means for aurora viewing at 54° magnetic latitude.

Common questions

Aurora watching from Seattle and western Washington State.

How often does Seattle see aurora?

Aurora events that meet the Kp 4-5 threshold for Seattle's 54° magnetic latitude occur on roughly 25-35 nights per year during solar maximum. The problem is that Seattle averages only about 160 clear nights annually, and many of the clearest nights fall in summer when darkness is too short. Realistic aurora-visible nights from a quality dark sky spot near Seattle total perhaps 8 to 15 per year in active solar periods. Driving east over the Cascades to the Leavenworth area roughly doubles that number by trading Seattle's marine cloud cover for the drier east-side climate.

What Kp is needed for aurora near Seattle?

Seattle sits at about 54° magnetic latitude, so the threshold is Kp 4 to 5. The Kp index is a global measure of geomagnetic activity on a scale from 0 (quiet) to 9 (extreme storm), updated every 3 hours. At Kp 4 from a dark, elevated position like Hurricane Ridge, aurora is plausible on the northern horizon. Kp 5 events produce reliable activity. The challenge is almost always cloud cover rather than geomagnetic activity - Seattle regularly misses Kp 5 events under overcast skies.

Why is cloud cover the main problem for Seattle aurora?

Seattle sits in the Pacific maritime climate zone where onshore flow delivers persistent low cloud and marine layer fog, especially from October through May - which is also aurora season. The Olympic and Cascade mountain ranges do little to block this moisture at Puget Sound elevations. The marine layer typically sits at 500 to 1,000 meters, which is why positions above it like Hurricane Ridge (1,640 meters) are so valuable. The Cascade rain shadow immediately east is the other solution - Ellensburg and Leavenworth average nearly twice as many clear nights as Seattle.

What are the best aurora spots east of the Cascades accessible from Seattle?

The Leavenworth area via US-2 is the closest quality dark sky position, about 2.5 hours from Seattle. Heading south, Ellensburg on I-90 is also 2 hours and offers open plateau terrain. Farther east, the Palouse region near Pullman reaches Bortle 2-3 conditions but requires 5 hours of driving. For a dedicated aurora trip with advance notice of a major storm, the eastern slopes of the Cascades above Leavenworth - accessible on Forest Service roads in summer - give both dark sky and dramatic mountain-and-valley foregrounds.

Does driving east over the Cascades actually improve aurora odds from Seattle?

Yes, substantially. The cloud cover difference between Seattle and Leavenworth on a typical fall or winter night is often the difference between zero visibility and clear sky. The Cascades act as a barrier to marine moisture, so east of the crest, cloud cover drops from roughly 75-80% in winter Seattle to 40-50% in the Leavenworth area. The 2.5-hour drive makes a same-night response to an aurora alert feasible when the forecast shows clearing on the east side. Checking two cloud forecasts - Seattle and Leavenworth - before any predicted storm is a standard practice for Washington state aurora observers.