Trader sentiment for Seattle's highest temperature on March 27 clusters tightly around 52-59°F, driven by the latest NOAA and ECMWF ensemble forecasts projecting daytime highs near 55-57°F amid a persistent marine layer and weak high-pressure ridge over the Pacific Northwest. These models show low confidence in extremes, with 70% of members clustering in the mid-50s due to cool onshore flow suppressing instability, while slight ensemble spreads account for the even odds on adjacent bins—warmer outliers from transient ridging push 58-59°F viability, cooler ones from enhanced cloud cover favor 52-53°F. Historical late-March normals (54-56°F) and transitioning El Niño patterns reinforce this balanced outlook, with NWS Seattle's afternoon update as the key near-term catalyst.