Official forecasts from the National Weather Service place Chicago’s June 9 high near 86°F under southerly flow, with scattered afternoon thunderstorms and increasing cloud cover expected to limit further warming. These conditions create the tight market clustering around the 86–89°F brackets, as modest shifts in storm timing or coverage could easily push readings one or two degrees higher or keep them capped in the mid-80s. Historical June climatology shows typical highs near 79°F, so the current warm anomaly stems from a broader Midwest heat pattern that has persisted into early June. Traders are weighting the latest model consensus and real-time observations, which continue to favor upper-80s peaks unless convection develops earlier than currently projected.