Recent forecasts from sources including the National Weather Service and private models indicate a Tuesday night low in Chicago near 55–58°F under persistent northeasterly flow and increasing cloud cover that limits radiational cooling. This follows a cool, breezy weekend that established a below-normal air mass across the region. The tight clustering of market-implied probabilities around 56–59°F reflects genuine forecast uncertainty in the exact overnight minimum, driven by small differences in model handling of wind speeds, cloud timing, and urban heat island effects. Historical averages place the date’s typical low at 56°F, providing a baseline traders are weighting against current guidance. Updated model runs and official NWS briefings over the next 48 hours will likely refine these odds ahead of resolution.