National Weather Service guidance and ensemble model consensus currently favor a Seattle high near 62°F on May 17, driven by persistent onshore flow from the cool Pacific that moderates daytime warming in the city’s maritime climate. This setup keeps temperatures tightly clustered around the low-to-mid 60s, producing the market’s near-even split between the 64°F-or-higher bucket (45.0%) and the 62-63°F range (35.5%). Minor variations in wind direction, cloud cover, or the exact timing of any sea-breeze shift can easily push the observed high across the 63–64°F threshold, which is why lower bins remain heavily discounted. Historical mid-May climatology for Sea-Tac shows average highs in the upper 50s to low 60s, underscoring how today’s conditions sit squarely within normal variability without strong warm or cold advection. Traders are therefore weighing the latest model runs and afternoon observation trends ahead of the official daily maximum reading.