Latest National Weather Service model consensus and ensemble guidance project a daily high of 63–67°F at Seattle-Tacoma International Airport on May 19, driven by a building thermal ridge and light easterly flow that limits marine layer intrusion. This outlook aligns with the market’s 96.5% implied probability for 58°F or higher, reflecting traders’ assessment of current atmospheric conditions and typical May climatology where highs average near 66°F. Minor cooling from increased onshore winds remains possible but would need to exceed forecast spread to drop below the dominant threshold, an outcome historical analogs show occurs in fewer than 5% of similar spring setups. Updated model runs on May 18 will provide the next key data point for any revisions.