Recent National Weather Service forecast guidance has converged on a daily high of 58–59°F at Seattle-Tacoma International Airport, the official station used for market resolution, producing the market’s 100% implied probability for that range. Mid-May climatology for the Pacific Northwest places typical highs in the upper 50s to low 60s under onshore marine flow, and current atmospheric conditions—including a lack of strong warm advection or offshore flow—support this narrow outcome. Model consensus across multiple runs reinforces the projection with minimal spread, leaving little room for significant deviation. Only an unexpected late-day surge in solar heating or a sharp shift in the marine layer could push the high into the 60–61°F bin, an eventuality traders have priced at just 0.1%.