Traders have converged overwhelmingly on an 80–81°F high for Seattle on August 4 because official National Weather Service observations and model consensus aligned precisely with that range. Afternoon temperatures peaked near 81°F under clear skies and light onshore flow, consistent with a brief warming episode embedded in an otherwise near-normal August pattern. This outcome sits just above the 1991–2020 climatological normal of 79°F yet well below historical extremes, reflecting typical late-summer variability driven by Pacific high-pressure ridging without significant heat advection. Minor forecast adjustments from earlier runs were quickly incorporated into market pricing, leaving negligible volume on adjacent bins. Only an unreported station error or post-hoc data revision could alter resolution, though such scenarios remain statistically improbable given multiple corroborating sensors.