Current forecast models indicate a highest temperature in Paris on September 30 most likely near 23–24°C, aligning with the market's tight leading probabilities. Southerly flow ahead of an approaching low-pressure system is expected to maintain mild conditions, yet widespread cloud cover and periods of rain or thunderstorms—particularly in the afternoon—will limit daytime heating and cap the peak. Ensemble guidance shows limited spread in maximum values, with precipitation timing and intensity as the main variables that could shift the outcome by 1°C. This setup exceeds the long-term average high of roughly 19°C for the date while falling well short of late-September extremes. Updated model runs and official Météo-France guidance through the evening of September 29 will provide the clearest signals for final resolution.