Ongoing heatwave conditions across northern France are the dominant driver pushing trader consensus toward 21–22°C as the August 4 overnight low in Paris, with implied probabilities clustered tightly around those levels. High-pressure subsidence, elevated humidity, and limited nocturnal radiative cooling under partly cloudy skies have produced “tropical nights” where minimum temperatures have remained above 20°C in recent days, well above the long-term August average of 14–16°C. Ensemble guidance from ECMWF and Météo-France currently clusters the expected minimum near 20–22°C, with only modest spread tied to small differences in cloud cover and wind. Resolution hinges on the final observed 24-hour minimum at official Paris stations; any late-model shift toward clearer skies or stronger northerly flow could pull the outcome lower, while persistent warm advection would favor the upper end of the 20–22°C range.