Trader consensus on Polymarket heavily favors a Chicago high of 42-43°F at 30% implied probability, driven by the latest NOAA GFS and ECMWF ensemble forecasts converging on mid-afternoon peaks near 43°F amid light southerly winds and partial cloud cover. Differentiating this from the close 44-45°F contender (23.5%) are subtle model discrepancies: the European model shows slightly warmer 850mb temperatures aloft, potentially adding 1-2°F if mixing strengthens, while GFS ensembles emphasize lingering morning clouds capping daytime heating. Historical late-March norms average 45°F, but today's cooler upper-air pattern—negative geopotential height anomalies over the Midwest—bolsters the lower bins, with key NWS updates expected by evening sharpening odds.