Recent National Weather Service guidance and ensemble model runs point to a high near 76°F for Chicago on September 6 under northeast flow, with most forecasts clustering in the upper 70s to low 80s inland and cooler readings near Lake Michigan. A frontal passage earlier in the week ended a stretch of mid-90s heat, allowing cooler, drier air to advect southward while partial cloud cover limits daytime heating. Lake-effect moderation and the exact position of the thermal gradient create the narrow spread among the leading 76–81°F bins; small shifts in wind speed, cloud timing, or boundary-layer mixing could push the official high across the 78–79°F or 80–81°F thresholds that currently share the highest implied probabilities. Updated model cycles and the NWS forecast discussion expected later today will likely refine these outcomes.