Multiple weather sources report conditions for the same place. Over time, their accuracy diverges. The marine air funneling up Possession Sound, the Puget Sound Convergence Zone forming over Mukilteo, the rain shadow edge at the Cascade foothills — each microclimate feature tests the models differently. Measure. Compare. Score. Let the data decide which source knows this place best.
Current Conditions — KPAE Paine Field
Tides Today — Everett (Station 9447659)
Mixed semidiurnal — two unequal highs and two unequal lows per day. Affects Mukilteo Lighthouse Beach, Picnic Point, Meadowdale Beach, Possession Point.
Artemis II — Crewed Lunar Flyby
Weather Source Leaderboard — Early Results
Weather Station Network
19 data sources across 3 tiers: 8 aviation METAR stations, 7 NWS/CWOP/NDBC stations, and 4 satellite/model sources. KPAE Paine Field is the primary ground truth — 2.5 mi from Mukilteo waterfront, 607 ft elevation on a bluff. Full station map and API details: Weather Data Source Map.
Aviation METAR/ASOS Stations
Automated Surface Observing System stations at airports. Temperature, wind, pressure, visibility, ceiling, present weather. Updated every minute (ASOS) with hourly METAR reports and special observations (SPECIs) when conditions change.
| Station | Location | Elev | Dist | Key Advantage | API |
|---|---|---|---|---|---|
| KPAE | Paine Field, Everett | 607 ft | 2.5 mi | Ground truth — closest ASOS to Mukilteo | METAR |
| KAWO | Arlington Municipal | 137 ft | 25 mi N | North reference — reveals PSCZ oscillation | METAR |
| KBFI | Boeing Field, Seattle | 21 ft | 28 mi S | Sea-level baseline — catches what hilltop KPAE misses | METAR |
| KSEA | Sea-Tac Airport | 433 ft | 25 mi S | Primary regional reference — official SEA climate records | METAR |
| KRNT | Renton Municipal | 32 ft | 30 mi SE | South Sound lowland — Lake Washington influence | METAR |
| KBVS | Skagit Regional | 144 ft | 36 mi N | Skagit Valley — convergence zone northern extent | METAR |
| KNUW | NAS Whidbey Island | 47 ft | 28 mi NW | Marine exposure — Strait of Juan de Fuca influence | METAR |
| KPWT | Bremerton National | 444 ft | 30 mi W | Kitsap Peninsula — cross-Sound comparison | METAR |
When the Puget Sound Convergence Zone is active, KPAE can report overcast/rain while KSEA (25 mi S) reports clear. Comparing KPAE vs KAWO reveals the PSCZ's north-south oscillation. KBFI at 21 ft captures sea-level conditions that hilltop KPAE misses.
NWS, CWOP & NDBC Stations
Citizen Weather Observer Program, National Data Buoy Center, and cooperative network stations. These fill gaps between airports and add marine coverage.
| Station | Location | Type | Measures | Update |
|---|---|---|---|---|
| C2882 | Anacortes | CWOP | Temp, humidity, wind, pressure, rain | 5-10 min |
| C5456 | Hansville (N Kitsap) | CWOP | Temp, humidity, wind, pressure, rain | 5-10 min |
| C8405 | Kingston | CWOP | Temp, humidity, wind, pressure, rain | 5-10 min |
| D2629 | Snohomish | CWOP | Temp, humidity, wind, pressure, rain | 5-10 min |
| SEAW1 | NWS WFO Seattle | NWS Coop | Temp, humidity, wind, pressure | Hourly |
| WPOW1 | West Point (47.66N 122.44W) | NDBC CMAN | Wind, temp, pressure — marine exposure | 6 min |
| EBSW1 | Elliott Bay (47.60N 122.34W) | NDBC NOS | Wind, temp, water level | 6 min |
Forecast Models & Satellite Sources
| Source | Grid / Coverage | Type | Resolution | Update |
|---|---|---|---|---|
| NWS Forecast | SEW grid (47.9N 122.3W) | GFS/NAM blend | 2.5 km | Hourly |
| Open-Meteo | 47.9N 122.3W | ICON/ERA5/HRRR | 1-3 km | Hourly |
| PurpleAir | Mukilteo sensors | Community IoT | Hyperlocal | 2 min (temp only) |
| Personal Station | Home | Direct observation | Point | Continuous |
Weather Source Accuracy Scoring
Each source sampled during periodic sweeps. Accuracy scored against KPAE actuals over rolling 30-day windows. See scoring methodology for MAE, F1, and Brier score calculations.
| Source | Temp MAE | Wind Acc | Precip F1 | Notes |
|---|---|---|---|---|
| KPAE | Ground truth (reference) | 607 ft bluff — 2-3°C warmer than waterfront on calm nights | ||
| NWS Forecast | 0.23°C | 3/3 wind | -- | Leading on temp accuracy — GFS/NAM blend captures local terrain |
| Open-Meteo | 0.41°C | 2/3 wind | -- | ICON model good on trends, misses rapid marine layer shifts |
| KSEA | 0.68°C | 2/3 wind | -- | 25 mi offset — misses PSCZ events entirely, good for regional baseline |
| PurpleAir | -- | -- | -- | Temp only — hyperlocal but uncalibrated, no wind/precip |
| Personal | -- | -- | -- | Pending deployment — will be waterfront reference at sea level |
Early scoring — 3 samples collected. NWS leading with lowest temperature error and perfect wind direction matches. See full station map for geographic context and API endpoints.
Scoring Methodology
Temperature MAE
Mean absolute error in °C between predicted and actual temperature. Lower is better. Scored over rolling 30-day window. Accounts for microclimate variation between airport and waterfront.
Wind Accuracy
Combined direction error (degrees) and speed ratio. Marine wind channeling up Possession Sound creates local patterns that regional models often miss.
Precipitation F1
F1 score for binary rain prediction (did it rain when they said it would?). Puget Sound Convergence Zone makes this the hardest metric — rain can fall on Mukilteo while Everett stays dry.
Fog Prediction
Dewpoint spread < 2.5°C predicts fog. Score: did fog actually form? Radiation fog on calm clear nights, advection fog off Possession Sound. Binary classification F1.
Confidence Calibration
Brier score — when they say 80% chance of rain, does it rain 80% of the time? Measures whether probability forecasts are well-calibrated, not just whether they're right.
Timing Accuracy
Hours off on front arrival. When the forecast says rain starts at 2 PM, does it? Convergence Zone events are notoriously hard to time — this metric reveals which models handle them.
Local Transit
Ferry schedules, loading estimates, and connections to regional transit.
Mukilteo — Clinton Ferry
Washington State Ferries route connecting Mukilteo to Whidbey Island. 20-minute crossing. History of the Black Ball Line, weather impact on operations, and the $187M new terminal.
Edmonds — Kingston Ferry
WSF route connecting Edmonds to Kingston (Kitsap Peninsula). 30-minute crossing. Commuter corridor to Olympic Peninsula. Edmonds is 8 miles south of Mukilteo.
Light Rail Connection
Link 1 Line (Lynnwood to Sea-Tac) and new 2 Line (cross-lake to Bellevue/Redmond). Bus connections from Mukilteo via Community Transit Route 113. Trip planning guide.
Sounder Train
Sounder N Line: Everett — Mukilteo — Edmonds — Seattle. Waterfront commuter rail with Puget Sound views. Plus Community Transit Swift BRT network.
Microclimate Features
Puget Sound Convergence Zone
When marine air splits around the Olympic Mountains, the two streams converge over north King County / south Snohomish County. This creates a narrow band of heavy precipitation that can dump rain on Mukilteo while Everett stays dry. The PSCZ is the primary source of forecast error for this location.
Possession Sound Marine Layer
Cool marine air funnels up Possession Sound from the Strait of Juan de Fuca. Creates morning fog, moderates temperatures, and channels wind differently than inland stations report. KPAE sits at the airport, 2 miles from the waterfront — the microclimate differs.
Cascade Rain Shadow Edge
Mukilteo sits at the western edge of the Cascade rain shadow transition. Annual precipitation drops sharply east of the Cascades. The foothills to the east receive more orographic lift precipitation than the waterfront. Elevation matters at every scale.
Tidal Influence on Air Temperature
Large tidal exchanges in Possession Sound affect nearshore air temperature and humidity. Low tide exposes mudflats that warm differently than open water. The 12.4-hour tidal cycle overlays the 24-hour diurnal cycle, creating beat frequencies in temperature and fog formation.
Waterfront Parks & Beaches (North to South)
Puget Sound shoreline from Kayak Point south through Mukilteo and Edmonds to Seattle. Tides affect beach access, fishing, and boat launching at all locations. Full guide with history, access, and ecology →
Kayak Point County Park
300-foot fishing pier, boat launch, beach access. Best crabbing pier in Snohomish County. Low tide exposes extensive tidal flats. Camping available.
Mukilteo Lighthouse Park
Historic lighthouse (1906), accessible beach, picnic area, boat launch. Adjacent to the new Mukilteo ferry terminal fishing pier. Coho and Pink salmon when in season.
Picnic Point Park
Snohomish County park with 700 feet of shoreline, beach access at low tide, trail through ravine to the water. Quiet, less crowded than Mukilteo.
Meadowdale Beach Park
1.25-mile trail through old-growth forest to beach. Loons Creek estuary. Best low-tide beachcombing south of Mukilteo. No vehicle access to beach.
Edmonds Waterfront
Fishing pier (219 Railroad Ave), Brackett's Landing (underwater dive park), marina, beach. Marine sanctuary protects tidal zone. Ferry terminal adjacent.
Carkeek Park
Beach access via pedestrian bridge over railroad tracks. Piper's Creek salmon spawning (Nov-Dec). Tide pools at low tide. 220 acres of forest trails.
Golden Gardens Park
Largest public beach in north Seattle. Boat launch, fire pits, off-leash dog area. Views of Olympic Mountains. Popular sunset spot.
Boat Launches & Marinas
Public launch ramps for recreational watercraft. Fees vary. Tide-dependent launches require checking water levels before trailering. Full boating guide with Ballard Locks and Lake Washington →
Port of Everett Boat Launch
13-lane launch, direct access to North Puget Sound. $15/day includes trailer parking. Gateway to Possession Sound crabbing, salmon fishing, and Whidbey Island waters.
Mukilteo Lighthouse Boat Launch
Single-lane ramp at Lighthouse Park. Free. Tide-dependent — check water level before launching. Direct access to Possession Sound.
Edmonds Marina
Public boat launch at Port of Edmonds. Access to central Puget Sound. Close to Edmonds-Kingston ferry route — watch for ferry traffic.
Shilshole Bay Marina
Port of Seattle marina with boat launch. Access to Puget Sound via Shilshole Bay. Gateway to the Ship Canal and Ballard Locks for Lake Washington access.
Ballard Locks & Lake Washington
The Hiram M. Chittenden Locks connect Puget Sound (salt water) to Lake Washington (fresh water) via the Ship Canal. The locks handle more boat traffic than any other lock in the US. Full boating guide →
Hiram M. Chittenden Locks (Ballard Locks)
Open daily 7 AM – 9 PM. Free passage for all vessels (kayaks to 760-foot ships). Water level drops up to 26 feet. 10-15 minute transit. Fish ladder for salmon viewing (Jun-Nov). Carl S. English Jr. Botanical Garden on grounds. Over 1 million visitors/year.
Lake Washington Access
Magnuson Park (Sand Point) — public boat launch, beach, fishing pier.
Gene Coulon Park (Renton) — south end, boat launch, fishing pier, swimming.
Luther Burbank Park (Mercer Island) — north end, fishing dock, swimming.
Kenmore — north end launch ramp, access to Sammamish River.
Kirkland — Marina Park, Waverly Park fishing piers.
Fishing — Lake Washington
Species: Chinook, Coho, Sockeye salmon (seasonal), rainbow trout, largemouth bass, smallmouth bass, yellow perch, coastal cutthroat trout. Bank access abundant. Numerous fishing piers around perimeter. WDFW regulations.
Fishing — Puget Sound
Full fishing guide with species, seasons, regulations →
Salmon Fishing Piers
Mukilteo fishing pier (new, at ferry terminal) — Coho, Pink salmon in season.
Edmonds pier — year-round fishing, squid jigging at night.
Everett Jetty Landing — adjacent to boat launch.
Kayak Point pier — 300 ft, best Dungeness crab pier in county.
Crabbing & Shrimping
Possession Sound and Port Gardner are productive Dungeness crab grounds accessible from the Everett boat launch. WDFW sets seasonal openings (typically summer/fall). Shrimp pots in deeper water (100-300 ft).
Safety & Navigation
NOAA Chart 18443 (Puget Sound, northern part). Watch for ferry traffic on Mukilteo-Clinton and Edmonds-Kingston routes. Possession Sound has commercial shipping traffic to/from Port of Everett. Tidal currents strongest at Admiralty Inlet and Deception Pass.
Light Rail & Transit
Sound Transit Link light rail connects Lynnwood to Seattle to Bellevue to Redmond. Community Transit buses connect Mukilteo/Everett to Lynnwood station. Full transit guide with trip planning →
Sound Transit 1 Line
Lynnwood City Center → Northgate → U District → Capitol Hill → Westlake (downtown) → Pioneer Square → Stadium → SODO → Rainier Beach → Tukwila → Sea-Tac Airport → Angle Lake. Frequent service, ~45 min Lynnwood to Sea-Tac.
Sound Transit 2 Line (Crosslake)
Lynnwood → Northgate → U District → Capitol Hill → Judkins Park → Mercer Island → Bellevue Downtown → Spring District → Bel-Red → Overlake → Downtown Redmond. 25 stations, 33 miles. First light rail across Lake Washington.
Sounder N Line (Commuter Rail)
Everett → Mukilteo → Edmonds → King Street Station (Seattle). Waterfront route along Puget Sound. Peak hours only (AM southbound, PM northbound). ~60 min Everett to Seattle.
Bus Connections to Light Rail
Community Transit serves Mukilteo, Everett, Lynnwood. Route 113 connects Mukilteo ferry terminal to Lynnwood Transit Center (1 Line station). Swift Blue Line (BRT) connects Everett to Shoreline/Aurora.
King County Metro serves Seattle. Connects to all Link stations.
Data Sources & APIs
All sources are free, no API keys required. Rate limits are reasonable for periodic polling. Full endpoint documentation: Weather Data Source Map.
| Source | Endpoint | Data | Update |
|---|---|---|---|
| Aviation Weather | |||
| NOAA KPAE | api.weather.gov/stations/KPAE/observations/latest | Full METAR: temp, dew, wind, vis, ceiling, pressure, wx | ~5 min |
| NOAA KSEA | api.weather.gov/stations/KSEA/observations/latest | Full METAR (regional reference) | ~5 min |
| NOAA KBFI | api.weather.gov/stations/KBFI/observations/latest | Full METAR (sea-level baseline) | ~5 min |
| AWC METAR | aviationweather.gov/data/metar/?ids=KPAE,KAWO,KBFI,KSEA | Multi-station raw METAR text | Hourly + SPECI |
| Tides & Water | |||
| NOAA Tides | api.tidesandcurrents.noaa.gov (9447659) | Hi/Lo predictions, water level, water temp, air temp, wind, pressure | 6 min |
| USGS Snohomish | waterservices.usgs.gov (12150800) | River flow (cfs) + gage height | 15 min |
| Forecasts & Models | |||
| NWS Forecast | api.weather.gov/gridpoints/SEW/129,82/forecast/hourly | 7-day hourly forecast (GFS/NAM blend, 2.5 km grid) | Hourly |
| Open-Meteo | api.open-meteo.com/v1/forecast?latitude=47.9&longitude=-122.3 | Multi-model (ICON, ERA5, HRRR), 1-3 km resolution | Hourly |
| Synoptic Data | api.synopticdata.com/v2/stations/latest | 170K+ stations, 320+ networks, radius search (ASOS, CWOP, RAWS, DOT) | Varies |
| Space Weather & Marine | |||
| NOAA Kp Index | services.swpc.noaa.gov/products/noaa-planetary-k-index.json | Geomagnetic activity (Kp 0-9) | 3 hours |
| SWPC Solar Wind | services.swpc.noaa.gov/products/solar-wind | Speed, density, IMF Bz, proton flux | 1 min |
| NDBC WPOW1 | ndbc.noaa.gov/station_page.php?station=WPOW1 | West Point CMAN — marine wind, temp, pressure | 6 min |
| NDBC EBSW1 | ndbc.noaa.gov/station_page.php?station=EBSW1 | Elliott Bay NOS — wind, temp, water level | 6 min |
| Transit | |||
| WSDOT Ferries | wsdot.wa.gov/ferries/api | Vessel positions, schedules, loading estimates | Real-time |
| JPL Horizons | ssd.jpl.nasa.gov/api/horizons.api | Sun/Moon ephemeris for 47.9N (rise, set, phase, illumination) | On demand |