**Trader consensus centers on an unusually warm overnight low of 78–79°F (91.5% implied probability) for Chicago on September 2, 2026, driven by National Weather Service guidance and model consensus showing persistent heat and humidity.** Official forecasts from NWS Chicago and supporting sources project a high near 92–94°F today under mostly sunny skies with southwest winds, followed by a low of 75–80°F tonight. Partly cloudy conditions, a stationary frontal boundary, and limited radiational cooling under humid air (dew points in the low-to-mid 70s) are expected to keep temperatures elevated. This places the minimum squarely in the upper 70s, consistent with the market's dominant outcome and well above the long-term September 2 average low of ~64°F. Key supporting factors include heat indices reaching 100–105°F during the day, ongoing southerly flow, and only a 30% chance of late-night showers or thunderstorms that are unlikely to produce significant cooling. The 67°F-or-below outcome (49.0%) and cooler ranges carry far lower odds because current atmospheric conditions and short-range models show little potential for rapid temperature drops. Realistic challenges to the 78–79°F consensus would require stronger or earlier convection bringing cooler air aloft, a sharper wind shift promoting radiational cooling, or measurement adjustments at official stations (e.g., O’Hare or Midway). However, the latest NWS point forecast matrices and area discussions indicate high confidence in the warm minimum, with any changes likely to emerge only from updated model runs or real-time observations overnight.