Current ensemble forecasts from Météo-France and ECMWF place the overnight minimum in central Paris near 17–19 °C for July 17, with modest spread arising from uncertainty in nocturnal cloud cover and boundary-layer mixing under a lingering warm, stable airmass. Recent heatwave conditions have elevated baseline temperatures, while the urban heat-island effect consistently adds 1–2 °C to observed lows relative to model grid points. Traders assign the highest implied probability to 18 °C because that outcome aligns with the median of latest high-resolution runs, yet the tight clustering of probabilities across 15–22 °C brackets reflects genuine model divergence on whether clear skies or increased low-level moisture will allow further radiational cooling. Updated guidance expected within 24 hours will likely narrow the distribution ahead of market resolution.