Trader consensus on Polymarket heavily favors Chicago's highest temperature at O'Hare International Airport falling in the 80-81°F (41.5%) or 82-83°F (34.5%) bins, driven by the National Weather Service's latest morning forecast projecting highs near 81-82°F under breezy south winds of 15-25 mph advecting warm air from the south. Dense fog lingering until mid-morning has delayed the warmup from current readings around 50-70°F, but model consensus anticipates partly sunny skies allowing peaks in the early afternoon before a 20% chance of showers and thunderstorms introduces cloudiness. Differentiating factors include exact fog dissipation timing, wind-driven mixing, and potential convective inhibition; historical April 17 normals hover near 60°F, making this 20-25°F anomaly reliant on sustained advection without disruptive precipitation, with afternoon forecast updates key to refining trader positions.