**Warm southerly flow and high humidity are sustaining elevated overnight lows across the Chicago area ahead of September 2.** Official model guidance and agency forecasts indicate a persistent warm air mass with southwest winds, limiting radiative cooling and keeping minimum temperatures in the mid-to-upper 70s°F rather than seasonal norms near 63–64°F. Recent conditions, including heat indices near 100°F and only modest overnight drops, reinforce this pattern, while any cloud cover or thunderstorm activity after midnight could further suppress cooling. Trader sentiment remains balanced across temperature bins because small forecast shifts—such as updated model runs from NOAA or NWS—could determine whether the low settles near 74–78°F or edges higher, highlighting the inherent uncertainty in precise overnight minimums under these conditions.