Recent National Weather Service model runs and supporting numerical guidance have converged on a daily high near 58–59 °F at Seattle-Tacoma International Airport, driving the overwhelming 98.8 % market-implied probability for that bin. Seattle’s mid-May maritime climate, with persistent onshore flow from the cool Pacific, typically caps afternoon temperatures in the upper 50s absent strong downslope warming or clear-sky radiative heating. Historical climatology places average highs for this date in the same narrow range, reinforcing trader consensus that deviations into the low 60s or below 57 °F are unlikely. The market could shift only if late-day observations reveal an unanticipated increase in solar insolation or a sharp change in boundary-layer mixing.