Ensemble forecasts from Météo-France and European models indicate mostly cloudy skies with light winds across Paris on May 17, limiting solar insolation and capping the daily maximum temperature near 15–16 °C at the official Montsouris station. This tight clustering arises because variable stratus thickness and brief sun breaks can alter peak heating by 1–2 °C through differences in radiative forcing and boundary-layer mixing. Historical May climatology shows typical maxima around 18 °C, yet recent upstream Atlantic flow has introduced cooler maritime air, keeping surface temperatures suppressed relative to clear-sky potential. Updated model runs tomorrow morning will refine cloud timing and resolve whether the high settles at 15 °C or edges to 16 °C.