Recent ensemble forecasts from Météo-France and ECMWF models indicate overnight lows near 19–20 °C for Paris on June 16, driven by persistent high pressure, light southerly flow, and limited radiative cooling under partly cloudy skies. These conditions suppress the typical June nocturnal drop of 8–12 °C below daytime maxima, while the urban heat island at the Paris-Le Bourget reference station adds 1–2 °C. Traders assign the highest implied probabilities to 19 °C and 20 °C because model spreads remain narrow but straddle those thresholds, with minor differences in boundary-layer moisture and wind speed determining the exact minimum. A late shift toward clearer skies or stronger radiational cooling could push readings toward 18 °C, whereas any increase in cloud cover or warm advection would favor the upper end of the distribution.